Conference napalm::guitar

    Yo Jay...
    
    Maybe you wanna shed some more light from a recent reply as to why i
    should switch from EL34 to KT90 output tubes?
    
    Buck, an EL34 lover

      Ditto ... I'm interested as well. Are the KT-90's a NEW tube? Are
    there any special biasing considerations? Hmmmm- there's quite a few
    tube amp users here in this conference!  Are the Chinese 12AX7's
    marketed under any one specific brand name?
    
    						-BooM-

    It's been suggested I shouldn't place the head of my amp on the
    speaker cabinet. The head is an old fender bandmaster, the bottom
    has two 15" speakers, and I play bass through it (sorry Fred, I forgot
    what you told me earlier). 

                    -< Maybe not that much of a problem... >-

	I could see where the vibrations might, over time, damage the
	tubes, but.. My Twin Reverb (Which I play Bass thru on many
	occasions) hasn't seemed to have tube problems (I've done over 100
	gigs this year on it). It's probably 100 times harder on them just
	to move it accross black-top parking lots & up stairs (it has
	wheels).

	Besides, bandmasters, and bassmans, and all other manner of tube
	amplifiers were designed to be placed on thier speaker cabinets.
	I used a bassman for years like this withoout any tube failures.

	The tubes would last longer if you kept the amp head in a freezer
	while you played it, but that's a bit inconvienent.. Use a fan
	if you really want to keep the tubes cooler.

							Jens

    When I was shopping today, I was talking to a guy about 6L6's for my
    Kitty.  He said, "Stick with your EL34s!  Everyone is dumping their
    6L6s for EL34s!"
    
    Mike

    
    It was my understanding that EL34's were desireable for that "ball
    crushing" crunch...
    
    J.

    Thanks for the additions, I'll try to shed some light, if I can:
    
    1: The EL34 and 6L6 are nowhere near the same sounding tube.  Many
    factors, including voltage, bias, screen resistors etc are NOT the
    same.  A rule of thumb is, you can use EL34's in a 6L6 amp, but NEVER
    the other way.  The EL34 is a much stronger tube, voltage wise, and
    never reaches the 'crunch' in a 6L6 amp.  I would not bother.
    
    2: There are many differant EL34 type tubes, the best, if you can
    find them, is the GEC KT77.  Otherwise, the squareish top bottle
    units are the best choice.  When Marshall started using 6550's, it was 
    because Korg, then Merson/Univox wanted more power, stronger tubes, and
    to avoid inport taxes, as units shipped without tubes were taxed as
    'electronic parts', not 'amplifiers.  6550's shound like crap, and
    using EL34's in Marshalls gives that 'ol british crunch' you hear
    on records, although many metal freaks use 6550's just for the
    power and that they take longer to crunch, and since many use alot
    of effects, it seems to balance out in the wash due to overloading of
    the front end.  ONLY the USA and Japan got amps with 6550's.
    
    3: The new tube, soon to arrive, the KT90 is really a mix between the 
    EL34 and the king of output tubes, the KT88.  Higher voltages, up to
    800 vts, and 1 amp of current means two tubes, in the right circuit
    would put out 165 watts rms!!!!  Test of samples gave 150 watts rms
    out of a 100 watt Marshall.  The real gem of this tube is that it can
    be used in any amy set for EL34's, 6550's, KT88's or 6CA7's (which
    are a mix of EL34 & 6550, not a great tube.  WATCH OUT! many folks
    who sell what they call a EL34 may ship a 6CA7!!!) with a bias range
    of -30 to -75 volts!  The first samples I got were quite strong, and
    with luck I should get some to offer here soon. EST price: $30 ea
    in matched sets.    I have data sheets if anyone wants them, e-mail
    me if you do.
    
    4: the 12AX7 from china is the best tube they make so far. SOOOOOOO
    quiet, ringing and poping is a thing of the past.  Soon, I can offer
    some if anyone needs them, but my current stock is empty.  There is no
    real way of knowing if they are real, as most folks are dumping the
    older 12AX7's because they sound so noisy.  And remember, the 7025 is
    NOT a 12AX7!  Avoid anything marked this way, it is NOT a good sounding
    tube.  It was designed with 'low noise' in mind, but never made the
    grade, and high end suffers!  Real crap,and the pitts in any British
    amp.  I know the Fender schematics show 7025 as preamp tubes, but 
    they don't use them now.
    
    5: If the tube sockets are strong, and the wires are connected well
    there is no reason to worry about using the amp head on the cabinet.
    
    What's next?  well, I'll talk about hi-tech replacements for the 12AX7, 
    12AT7 and a way of controling imput gain with $1.50 of parts. Then,
    we'll talk about Class-A biasing, A la Vox AC30.  If there is interest,
    we can start a amp building project.  How about adding the Vox
    'Top-Boost' control to any amp, giving 'glass-like' treble?  Keep up
    the interest. If anyony needs parts to repair or upgrade, let me know.
    
    Jay Tashjian
    
    

    While looking thru my piles of junk, I found 12 sets of a package
    I once sold of schematics, data sheets, modifications and lots
    of neat tube information, over 100 pages.  Items like:
    
    Output transformer less power amps   (TUBES, w/o output transformers)
    Mosfet/tube pre & power amps
    Marshall Fuzz & wah-wah schematics (cir:1969)
    Fuzz face & cry baby pedal schematics
    piles of odd tube data
    Gold lion Manuals (KT77 KT88's from the UK)
    Tone control mods W/ boosts.
    
    and lots more then I can list here.  I sold these for $100 a set then,
    and in copying alone, it's $30.  ONLY 12 to be had.  The 1st 12 for 
    $40 each get them.  I'll include as much newer things as I can find, 
    like the Marshall reverb/fuzz unit, the Hendrix mod for fuzz-faces,
    the tube/mosfet/transistor 'tri-brid' frame of mind, and much more.
    
    Also, I have transformers (power & output) for 50 watt Sunns, Ampeg
    VT-2, SVT, & the like. If you want to 'roll yer own', e-mail me for
    prices.  100's of tube sockets, Filter caps, etc.  I want to clean
    this out, as I have no room to store them.
    
    HELP !    HELP!   HELP!   I need the room!
    
    The paper work is far beyond what you may have in the GT book, and
    took me 10 years to collect, from the US, UK, & Japan.  85% cannot
    be found anywhere else.
    
    Send Money Order to:
    
    John Tashjian
    p.o. Box 189
    Worcester, Ma.  01602
    
    

    FLASH!!!!!
    
    Due to the requests I have gotten, I'll include in the packages
    from the last note:
    
    Copies of old Marshall, Orange, Vox (tube), Hiwatt, & Mattamp
    catalogs.  Xerox, of course, but good copies.  Years of history
    to enjoy!
    
    As you can see, I really want to make room.
    
    Also, 12AX7WA tubes from China:  $5.00 each!!!  only 75 at this time!
    
    reply to Jay, see last note for address!
    
    (Note, I never planned this to be a 'sales' note section.  I just
    figured to unload these sets.  You will see, this is a one shot deal,
    save if folks need tubes and cannot find them elsewhere)
    

    Thanks to everyone for all the mail.  Yes, I will offer tube parts for
    sale thru the 'for sale' area, so not to upset the powers that be. 
    Look for the notice as "tubes, etc" by 10/13/90.  I really don't want
    to get heavy into selling them, but it seems no one can get good tubes,
    and/or parts.  We'll see how it goes.
    
    Anyway, it's lunch time, 3:00am, and I thought I'd answer a few ??????s
    on amplifier companies:
    
    1: Kitty Hawk is out of business.  The owners, a married couple, got
       divorced, and she got the company, the main business being building
       transformers.  Rumor has it, they may get back up soon.
    
    2: Orange has been out of business for years, the units you see being
       sold as new were found in a warehouse last year.  they are new.
    
       By the way, to change a 50 watt Orange to 120 watts, just add
       2 tube sockets, resistors and tubes.  The transformers are the same!
    
    3: Hiwatt is now owned by Japan, and being built in N.Y. by the same
       folks who build Jackson and Sundown, a generic company who builds
       to order.  The Hiwatts are great though.  Support them!
    
    4: Rumor!!! Boogie is about to be sold!  watch this space.!
    
    5: Sunn is owned by Fender, who only builds lighting equipment
       under the Sunn name.  ALL new Fender amps are built in the old
       Sunn factory!
    
    6: Duncan amps are built in overseas!  NOT IN Japan or the U.K.!
       but in Korea!
    
    7: Fact!  Only the Vox AC-30 is a TRUR Class-A amp.  Vox is built
       by Rose Morris in the UK, the old Marshall Dist. house.
    
    
    More on Friday.  Gotta go back to work.  Watch this space!
    
    Jay Tashjian
    

    4: Rumor!!! Boogie is about to be sold!  watch this space.!
    
    Let's hope Randall Smith remains in the loop.
    
    5: Sunn is owned by Fender, who only builds lighting equipment
       under the Sunn name.  ALL new Fender amps are built in the old
       Sunn factory!
    
    Just a nit, but the Sunn name also appears on PA equipment. All of
    the new Fender *Tube* amps (and a few of the solid state amps) are
    made in the Sunn factory, but most of the solid state combos are
    built in the far east (ie: the sidekicks, Squires, etc). I believe
    the rack-mount bass head is made in the Sunn factory. As far as I 
    know the solid state M80's are built in the far east.
    
    Mark

    Thanks to everyone for the support.  Here's some updates:
    
    1: Look for the ad under for sale for tubes & related items.
    
    2: Rumor cont...  Randle Smith seems to be the one interested
       in selling.  I hope not, because he knows his stuff, even 
       if the new items have far too many controls.  The old stuff,
       starting when he sold thru 'Prune Music' were great because
       they were so simple.  Japan seems to be the biggest offer
       for Boogie so far.   Watch this space.
    
    3: Both Gibson & Gretsch will come out with *!SUPER!* new 1-12
       Class-A amps!  Try them out!  Unbelivable.
    
    4: The KT90 will be out in about 90 days, watch for them here,
       under 'for sale'.
    
    5: Marshall 900's are having major troubles with screen resistors!
       replace with 5-10 watt units.
    
    6: FACT! The Marshall knob that goes to '12' is just a printing
       change on the control panel.  Numbers on panels are a state
       of mind.  The Marshall rack mount stuff is NOT the best of
       it's kind around.  Nor is the Boogie.  The strongest rack
       mount is the new Hiwatt.  Pure fact!
    
    7: FACT!  If you look at the Acoustic copy of the Boogie amp,
       you find they are almost 100% the same.  Fact is, Acoustic
       'rented' a Boogie, copied it, and got sued off their ass
       as a result.  The Acoustic was a pile of Sh*t, and they
       deserved to get nailed.
    
    8: WANTED !!!  Anyone got a amp called 'DELTA' with the 8-track
       cartridge echo unit built in it?  Cabinet(s) were 4-10" &
       2-12".  E-Mail me, even if you only have the head for sale.
    
    9: FACT!  Remember 'WEST' amps, used by Grand Funk Railroad?  The
       ones used onstage had Marshall guts!  The ones sold here
       had crap guts!  Pure Fact.
    
    Thats all for now, more to come later.
    
    Jay Tashjian
    

    Since folks have asked about good books to read about tubes, here
    are a few:
    
    The Williamson Amplifier              $4.95    Old Colony sound lab
    Audio Amateur magazine                         ""    ""    ""   ""
    Glass Audio (!!!!!!!!!!!)                      ""    ""    ""   ""
    RCA Data Book                          If you can find a copy...
    GEC/Gold lion manual                   E-mail me if you want a copy $9
    Audio Anthology #1, #2, #3            $42.00  (all 3)
    GE Tube manual                         If you can find a copy...
    Groove Tube amp manual   (great!)     $15.00 and worth it
    
    Other then that, books are hard to come by.   I'm checking into
    getting reprints of some European Manuals.   I'll keep you informed.
    
    And of course, My set 'package of papers' listed elsewhere.  
    
    Hint..Hint..   only 9 sets left, then no more!
    
    
    Other then that, watch this space...
    
    Next week, a list of companies that sell the goodies to anyone,
    anywhere.  All the right catalogs to own.  Watch this space!
    
    Jay Tashjian
    

    
    	Jay...
    
    	Regarding the Boggie copy/swipe by Acoustic:
    
    	I've had my Acoustic for a few years now. I've heard that story
    once before but I wasn't sure if I believed it. Now I do. I think 
    the amp is all right; it doesn't knock me out, but I can get the
    sound I like out of it. 
    
    	My question is this:  You said that Acoustic took a Boogie and
    copied it-- you said they were "100% the same"-- but then you called
    it "a pile of sh*t". Does that mean a Boogie is a pile of excrement
    too? Is the Acoustic crap because they used inferior parts, or were
    you just calling it crap because of Acoustic's disreguard for copyright
    laws? Is the Acoustic amp a poorly built copy of a Boogie or is it
    really "100% the same"?
    
    	I'm not trying to play the devil's advocate with this, I'm just
    wondering how close to a Boogie is this heap? I've been thinking
    about selling it for a while now. Your answer will have a good deal
    of weight with my decision.
    
    
    	Brad Page
    
    
    P.S.-- What do you (or anyone else) think of Bedrock amps? (They're
    made in Nashua, N.H.)
    
    
     

    I HAVE A ORIGNAL COPY OF THE 1ST DRAFT OF THE ACOUSTIC COPY, AND IT IS
    SO CLOSE TO THE BOOGIE, IT SCARES ME.  IT WAS CRAP BECAUSE OF CHEAP
    TRANSFORMERS AND POOR WORKMANSHIP.  IF YOU HAVE A GOOD ONE, IT MUST
    BE AFTER THE LAWSUIT, WHEN THE WERE FORCED TO CHANGE MINOR PARTS, AND
    END PRODUCTION AFTER STOCK WAS SOLD. THERE ARE SOME CHANGES THAT WILL
    HELP KEEP IT RUNNING, E-MAIL IF YOU WANT THEM.
    
    BEDROCK AMPS ARE VERY WELL MADE, AND A GOOD BARGIN.  CHECK THEM OUT.
    
    FACT!:  REMEMBER MIGHTY-MITE PICKUPS?  EVERY (!) ONE WAS WOUND BY HAND
    BY PATIENTS AT A CA. MENTAL HOSPITAL!  MIGHTY MITE IS NOW J.B. PLAYER,
    ALTHOUGH I DON'T KNOW WHO DOES THE WORK NOW.  I KNOW THIS FROM 1ST HAND
    WHEN I WAS WORKING WITH MM IN CA YEARS AGO!  THE PATIENTS DID GOOD
    WORK, WORKED CHEAP, AND DIDN'T CARE WHY.  ALL HARDWARE FOR MM,
    SCHECTER, AND ALL THE OTHERS CAME FROM ONE SHOP, NOW CALLED ALL-PARTS!
    
    THE FACTS, NOTHING BUT THE FACTS......
    
    FACT!: THE SPEAKER CUTOUTS FOR THE 1ST BOOGIES WERE CUT FROM
    OUTHOUSE DOORS!
    
    FACT!: THE 1ST CARVIN AMPS WERE SOLID-STATE, SOLD THRU THE MAIL ONLY,
    AND KICKED BUTT!  IF YOU FIND ANY OLD (REAL OLD, 60'S) CARVINS,
    GRAB THEM.
    
    FACT!: GIBSON CAME WITHIN A 30 MINUTE DEADLINE OF BEING OWNED
    BY PEAVEY!
    
    FACT!: AMPEG IS NOW OWNED BF THE FOLKS WHO MAKE CRATE.  AMPEG SOLID
    STATE UNITS ARE BEEFED UP CRATE DESIGNS.  NOT BAD, BUT A CRATE IS A
    CRATE, IS A CRATE.
    
    FACT!: KUSTOM DID MAKE TUBE AMPS IN THE PADDED CABINETS.  VERY RARE!
    
    FACT:  VOX SOLID STATE AMPS WERE DESIGNED IN THE UK, NOT THE US.  THE
    UK SS AMPS SOUNDED BETTER THEN THE US/THOMAS ORGAN UNITS EVER PRETENDED
    TO.  WORKED BETTER TOO.  THE BLUE SPEAKERS IN US VOX SS AMPS ARE THE
    GREAT BLUE 'BULLDOG' UNITS.  BUY THE CABINETS, STEAL THE SPEAKERS!!!!
    
    
    JAY TASHJIAN
    

    FACTS.....
    
    FACT: THE ONLY DIFF BETWEEN A 80 WATT ORANGE HEAD AND A 120 IS
          2 OUTPUT TUBES.
    
    FACT: VOX AC30'S WITH TAN CASES AND THE RARE HEAD/CAB STACK AC30
          PUT OUT 60 WATTS RMS IN TRUE CLASS A!
    
    FACT: THE BOOGIE SIMLUCLASS IS *NOT* CLASS-A.
    
    FACT: 6CA7 AND EL34 TUBES ARE *NOT THE SAME*
    
    FACT: JIM MARSHALL DISLIKES HIS AMPS TO USE 6550'S
    
    FACT: KT88 TUBES IN A 100 WATT MARSHALL HEAD PUTS OUT 130 WATTS
          AND MUCH TIGHTER SOUND.
    
    FACT: I'M GOING HOME NOW, AND WILL LOG ON AGAIN TOMMORROW...
    
    JAY
    

    
    
    Could you please *TURN DOWN THE VOLUME*? All capital letter are
    considered "SHOUTING" in notes. Please use mixed cased. 
    
    Thanks,
    
    -Tom
    

    
    regarding the acoustic/boogie issue ....for a piece of crap
    Guitar Player sure gave 'em a great writeup as a good used amp 
    buy.........what gives????
    -Bill

    re     FACT: VOX AC30'S WITH TAN CASES AND THE RARE HEAD/CAB STACK AC30
           PUT OUT 60 WATTS RMS IN TRUE CLASS A!
        
    How about JMI VOX AC30s with the black cases?  I always thought these
    were essentially the same amps as the tan ones, just different
    cosmetics.
    
    Also, how about some tips on biasing?  I noticed in a previous reply
    you mentioned biasing "by ear" (get it to hum, then back off slightly).
    Will this work on any amp?  Is this the preferred way?
    
    I know someone who adjusts the bias according to plate current (e.g.,
    somewhere between 10ma and 40ma for a pair of 6V6s).  However, he
    has a funny way of measuring the current.  Instead of placing the
    ammeter in series with the plate circuit, he measures between the plate
    of the power tube and the center tap of the output transformer with
    everything still in circuit, effectively shunting the transformer winding.
    This is less hassle than desoldering wires, but I don't understand
    how it works.  What do you think of plate circuit current as a way to
    adjust bias, and what do you think of this current measurement scheme?
    
    /rick
    

    
    Biasing is hard on amps without having a scope.  With a scope,
    after adding a signal to the amp, view the screen wave and adjust
    the bias till the waveform looks clear and clean, no sharp edges.
    
    That's the way hi fi amps are done.  Guitar/bass units are
    not as easy, because settings, mainly any overdrive/gain boost
    controls, effect the waveform.  The schematics show a 'ideal'
    bias settings, but that depends on the tube condition.  Adjusting
    bias till one no longer hears 'hum' works only if the ground
    conditions are good.  No matter how you look at it, it's a job
    for someone who knows.  The best overall way is to use a DVM and a
    'Bias-probe' unit, sold I belive still thru Groove tubes.  I'll
    call them today to find out.  You plug a tube into the probe, then into
    the socket, and adjust it to a preset value of the DVM.  More details
    later.
    
    Adjusting the bias till hum is gone has one value, besides setting
    the bias right, it allows you to run as close to Class-A as your
    amp will allow.  
    
    What is Class-A?   that comes next note.....
    
    Jay Tashjian
    

    Class-A is a state the amp runs in, when the tubes are full "on"
    all the time, not switching on/off like with Class AB (B) units.
    
    In a push-pull circuit, one side is on then it switches to the other
    side.  In Class-A, both sides are on full tilt boogie with no
    switching, and the resulting switching distortion.  The trade off?
    
    Current draw (50% more), tube life (30% less), heat (50% more)
    
    So, why do it?  Well, when the tubes do not switch, they deliver
    the output sound with much more attack, more even-order distortion
    (desired!) and no delay waiting for the tubes to get in the correct
    phase.  ANYONE who has played a Vox AC30 knows why these items
    are so desired, and this is why.
    
    Also, any amp, regardless of class, runs Class-A when the volume is 
    low (1-3).  This is nature of the design.  The lower the bias, the
    closer to Class-A.  The Boogie is not 'true' Class-A, just closer.
    
    Notice: KT90 tubes are on the way!   stay tuned..
    
    Jay Tashjian
    

	3 hours is not enough. There are caps in the power supply circuits
	that can store enough juice to roll your socks up and down a few 
	times after 3 weeks.

	- work with an insulated screwdriver. Short all cap leads to the
	  chassis. Until you've done this, keep one hand in your pocket.

    I would not suggest the screwdriver idea, because it can destroy caps
    that are old.  Use it only on new caps.
    
    Jay
    

    My new Fender Twin has test points on the back which allow you to
    set the bias and balance with a DVM. There are 3 points, bias,
    gnd, and balance. The instruction are printed right on the back
    panel. First set the bias to .04v, then set the balance to 0v.
    
    I read about the bias probe in Aston Pittman's "Tube Amp Book",
    and thought of ordering one, but that was before I sold my older
    Twin Reverb amp. Just out of curiousity, how much do these things
    sells for ?
    
    I'm thinking of replacing all the preamp tubes in my Fender "The
    Twin" and my Mesa Boogie Studio Preamp. The preamp is not that old.
    I bought it in July, but it was a store demo model for a while.
    I should probably talk to you off line about some preamp tubes.
    
    Mark
    

    The points you talk about are connected to the cathodes of the output
    tubes.  Normanly, a 2 ohm 10 watt resistor is placed between that pin
    and ground, not just to ground as it's wired from the factory.
    
    This is pretty much what the bias probe does.  If folks want, I
    can post a listing of the most common bias settings (volts at
    that pin) for the most common amps.  The resistors can be left in full
    time without a change in sound.  The tubes run cooler with them
    installed anyway.  Use 10 watt resistors (min)!!!!!!!!!!!  One on
    each side of the push pull set is not enough.  One on EACH tube is
    a must.  By checking each tube, you will find if one tube is weak
    on a side.  The best bias mod would include a seperate bias pot/
    circuit for each tube!  If enough interest, I'll post a simple
    project mod for this.
    
    Remember...the more stable the bias, the better the sound!  High cap
    values help here.  But wait...what about a voltage regulator?
    What if it involved MOSFETS!!!! If the bias was regulated, and set thru
    a MOSFET????   JAY, ARE YOU MAD??????
    
    Yup, and I'll post it this week.  Cheap and easy to build if you know
    something about electronics (bare min!) And no, the signal NEVER
    passes thru anything but a tube.  And if folks want the best idea, how
    about a MOSFET B+ high voltage regulator?   What if it involved the
    sound of tube regulation, and the high tech of MOSFETS? 
    
    That will be posted if there is enough interest, it's no easy task....
    
    
    Till next time..
    
    Jay

    
|    5: Sunn is owned by Fender, who only builds lighting equipment
|       under the Sunn name.  ALL new Fender amps are built in the old
|       Sunn factory!
        
        I suppose  this means there's little to no hope of getting my
        old 100Watt Sunn head fixed then huh ? :^(
        
        They  made  a  sweet  little  bass  head  though.  .  .took a
        beating with nary a gripe !  :^)
        
        Matt

    Send me a note of your problems, I have alot of Sunn parts..
    
    Jay
    

    SUNN amps are one of the unsung hereos around, ya can buy then super
    cheap, and with new tubes, they sound great.  This, and Ampeg V-4
    V-2, etc are great buys.  If you find a Sunn 100/200S cheap in the
    store used, buy it, let the dealer pay his bills, etc, and you'll
    have a great amp, and a good set of transformers for any tube
    project.  
    
    JUST AVOID THE SOLID STATE UNITS.  The 'Beta' Mosfet was a load
    of crap, with alot of problems..!!!!...!!!!...!!!!...!!!!
    
    GRAB any 1000S/2000S or Model T you can find!
    
    Till tommorrow...
    
    Jay Tashjian

    
|    GRAB any 1000S/2000S or Model T you can find!
        
        Can remember  the  exact  model number but it is the 100 Watt
        tube head.  It worked fine, until one day after a jam session
        three years ago I  damaged the fuse holder in the back.  So I
        just whipped out the soldering  iron  and  replaced  the fuse
        holder.  All wirings were done  exactly  like  they  had been
        before.    I powered it up and  it  came  up  like  a  charm,
        however, less than 30 seconds later, I lost power completely.
        Fuse was fine.
        
        Since there aren't many shops in Vermont (Burlington) that do
        old tube amp repairs (none of which  I've  found  would  even
        think of working on an old Sunn), I've  had to let it sit for
        the past three years in hopes of finding another  one kicking
        around.  I believe the transformer kicked out on me (or maybe
        a tube ?) and since this unit is so old,  I'm  not  sure what
        size  the  transformer  is (besides BIG) or even if I can get
        replacement tubes for it.  (Without it costing me a mint !)  
        
        I  would  appreciate  any  and all help I could get to repair
        this or  information showing where I may be able to go to get
        it fixed.   (or for parts or.  .  .  .etc.) This was my first
        bass amp that I  bought back in 1979, and I would LOVE to get
        this beast fixed.  It  puts  my  Yamaha  to  shame,  and I've
        always loved the sound of a  tube amp anyway.  (Better bottom
        end  in my book and cheaper than robbing a bank to buy a  new
        Marshall ! :^))
        
        Matt

      Yeah, the Model T was a nicely designed unit. It could have used
    a little more gain in the preamp but I'm sure that wouldn't be a
    tough modification. If I found one at a good price I might scarf
    one up.
      Hey Jay, have you ever been inside a Kitty Hawk? Like a M1 head
    or one of the tube preamps. I don't know anything about them (8-})
    so I'd like to know what you think.
							-john R.

    Kitty hawk amps were nice designs, but many were poorly made, cheap
    parts & all.  The thing about KH was they had the best transformers
    around! Real solid built, strong stuff.  When the couple who owned
    the transformer company decided to built amps, they came up with some 
    real nice preamp designs.  I have a complete set of schematics, and
    are real nice circuits.  Now that the divorce is over, it seems the
    lady wishes only to build transformers, not amps.  A pity.
    
    The US dist, LP systems, sold the remaining stock out reallllllly cheap
    and there is talk that the name will return soon, by a new owner,
    with new designs.   If I get any news, I'll post it here.
    
    Jay Tashjian
    

Jay,

Your help to this conference is outstanding...as for the quiet, chinese
12AX7's, I'd like to (like Mark) get those into my Twin...the only prob-
lem is: how can you recognize them, and how do you get them in Europe
(Denmark).

Very interesting, this subject, I recall my young days (long ago), burning
my fingers on the damn things :-)!

Poul

    I agree Jay...the transformer I had in MY KH preamp was just
    WONDERFUL!!!  ;^)

      Jay - Thanks for all your info. It's hard finding techs that
    understand tubes these days! You don't have to tell a lot of the
    readers of this conference about the Kitty Hawk blowout of L.P.
    music groups stock. It was entirely done through the KH topic (1103.*).
    The people at L.P. music were shocked to be getting calls from all
    over the country asking for a amp. M1's went real fast and that model
    is one hell of a great sounding amp. The tube preamps were available
    from time to time, some of them were "fix-ups". 
      I got a letter back from Kitty Hawk back in March of this year saying
    they were still in the amp business. I also had heard about the divorce
    stuff and it seems that Wolfram Roy may not be involved in the company
    anymore which is interesting because the amp designs were his! The 
    letter I got was signed by Gundolf and Marianne Roy. Also the price
    list I got dated Jan 1990 had more down to earth prices than the 
    L.P. Music group list.
      Even though my M1's, Quattro preamp, and Testarossa preamps are
    killers, one of the more interesting KH amps I have is my M5 combo.
    It uses a quartet of 6V6 tubes, there's something special about the
    sound coming out of these! I absolutely love that sound, real warm!
    
    							-bOOm-

I just fixed my testerossa and I thought of everything in it the transformer
was the most obviously hacked up piece of crap in it. Looked to be US 
technology circa late 1940's...it was also quite quite fried, it had overheated
and the final heavy current load took it down. The replacement transformer 
doesn't even get warm, much less painfully hot. I do agree that other 
pieces of the design could have been more robust, especially the circuit
boards which require a fairly low temp soldering iron or the runs peel right up 
under the heat.

Now I remember why I wanted the testerossa again though...

dbii

        Jay (and anyone else who can help),
        
        I took  a look at the Sunn tonight and it's a Model-200S.  It
        has five tubes in  it as well as two HUGE transformers.  (140
        Watts total draw)
        
        The tubes are:
        
        GZ34 (5AR4) Sylvania
        7025 (Unsure who makes it)
        KT88 (Two) by GE (The JL 188-5 has a rattle in it somewhere)
        6AN8A Sylvania
        Sunn 3-6PT Transformer
        Jester Transformer (Unsure how big)
        
        Anyone know if tubes like  these  exist anymore ?  The serial
        number on this unit is 0010344, so I'll assume it's OLD.  
        
        Thanks for any and all info.   That would be the gnads to get
        this unit back up and thumpin' !
        
        Matt :^)

    Those tubes are available most anywhere, the "KT88" from GE are just
    relabeled 6550's, not 'real' KT88's.  Replace the 7025's with 12AX7As.
    
    The 6AN8A is now a 6AN8AX, but any 6AN8 will do.
    
    Yes, I'm sure eeveryone knew about the KH history, but since we
    had alot of talk, I thought I'd re-hash it.  I'd like a Xerox of the
    new catalogs/price list, if anyone can get them to me.
    
    The 12AX7A from China is told from older units because the insides are
    VERY different from the US/UK units.  I'll have a note on them next
    week.
    
    Jay Tashjian
    

    Gain and tubes are directly related, let me shed a little light, since
    I just read the 'Gain' notes and it's been on my mind:
    
    Different tubes handle high gain in different ways.  The 12AX7A is the
    only tube for 1st stage gain.  The 7025 does not 'clip' in the same
    way, and cannot handle high gain coming from other stages very well.  
    This is why Old Fender amps had few gain stages when using 7025s.  The
    12AT7A is the best for handling input gain, but is not good for 1st
    stage gain control, hench it is mainly used in the driver stages of
    the power amp area.  While the 12AT7A is not a 100% replacement for
    the 12AX7A, it is a good try if you find your overall output gain
    too muddy.  IT IS A MUST IN DRIVER STAGES FOR MARSHALLS!  You also
    find them in reverb/tremelo stages for most amps, because it is about
    the strongest preamp tube made.  Nuff said.
    
    Output tubes distortion is directly related to the size of the bottle,
    and the ammount of gases inside.  Bottle glass thickness also has a
    hand in this.  This is why the (real) EL-34 with it's thin, small
    bottle full dense of gas 'crunches' better then the 6550, with it's
    large bottle, thick glass, and the same ammount of gases.  The KT88
    has other reasons (internal part sizes, construction) that allows it
    to handle higher voltages and currents then either the EL34 or 6550,
    yet it's odd shape bottle, thinner then 6550 glass and very dense
    gases lets it crunch very well when pushed.  The KT90 has the guts
    of the KT88, with a bottle size of a EL34, and gases of the KT88,
    it's one hell of a tube.  1st tests were fantastic!!!  Other tubes,
    like the EL84 (a EL34 design in small form) and 6V6 ( a US EL85 clone)
    have their own sounds, and the 6L6 is it's own animal too, alittle
    like a 6550, with less power, and different elements.  
    
    Output transformers have alot to do with sound too, but since they
    are not available custom (unless you buy 1k or more of them) we take
    what we get, when we can get them.
    
    Next time?  well,I'll keep answering ?????? for now, and then we will
    get into Negative feedback (ugh!), and the reason some speakers sound
    better with some amps then others.  While we may move outside tubes
    every now and then, we will always be working with tube amps. I enjoy
    the feedback I've been getting, and never thought I'd have this many
    folks all talking tubes so quickly.  I've learned alot, and I hope I've
    helped you too.  I've been into tube guitar/bass amps for 18 years
    (I'm 35) and although I do work with computers (program games for 
    the Apple IIgs), Ialways seem to return to tube amps.  I'm hooked...
    
    
    Jay Tashjian
    P.O. box 189
    Worcester, Ma.  01602
    

        Thanks Jay !  Now all I have to do is fine a place that sells
        these little beauties.    Gonna'  start by replacing the KT88
        that's got the rattle  in  it.  (That's the weird shaped one,
        the other one is a standard looking tube.)
        
        You said that the KT88's had  a  weird shape to them.  I only
        have one (in the KT88 slots) that  has that weird shape.  The
        other one is a standard looking tube.   I  know  the  guy who
        owned it before me used to play in one  of  the  more popular
        bands in the Burlington, VT area, so he may have  made  a few
        tweeks/replacements himself.  
        
        Thanks again !  You have been a big help !
        
        Matt_hoping_he'll_soon_have_his_Sunn_rising_again_! :^)

    My source told me tonight, long distance, that the Mesa Boogie company
    is NO LONGER up for sale, has turned down a offer from Japan for big
    bucks, and settled for remaining a seperate company, although they
    may go public (sell stock) VERY soon, for as with every company, the
    dealers can't pay bills fast enough for the company to pay theirs.
    
    Also, watch for a BIG SELL OUT of TUBE Ampeg amps soon.  They will
    advertise them as "Big savings", but it is to dump stock, as it now
    seems true they will dump the tube line by 1991!  The units up for
    sale are very good, make the best deal with your dealer today!
    
    Rumors has it the Mitchel and ORANGE amps will be made again, the
    Mitchel in the US (no idea who yet) and Orange in Japan.  Japan
    has a VERY BIG interest in UK amp names for product.  More info soon!
    
    Remember, they now own Hiwatt.  Past rumors were that they once offered
    DANGER MONEY for Marshall, but 'ol Jim said "No F*cking way" (Quote).
    
    The above info, like all other rumors/facts come from folks inside
    the companies, suppliers, and key $$$$ people.  ALL are good sources.
    
    More tonight.  My phone bills will be jumping into overdrive today!
    
    Jay Tashjian
    

    Just got my package of tube stuff (thanks Jay).  It contains an
    unexpected bonus!  There is a reprint of 1984 Craig Anderton
    column on the Fuzz Face, which includes reader comments from
    a certain "Brian Rost from Westborough, Mass.".
    
    15 minutes of fame, eh Brian?

      Back to reply .28: It's probably not a good idea to short the
    Power Caps whether they are new or old... Use something like 
    a 1 or 2 watt resistor at (about)  4.7 ohms with some insulated
    wires to shunt them. It takes a little longer (few seconds) to 
    dissipate the energy, but it's worth it.
    
      Besides...Those nice blue sparks have a tendency to burn little
    dark spots in yer eyes.  
    
    /John

    All resistors across high voltage filter caps, be they bleeder or
    voltage division, should be 2-watt.  Also, most any resistor in the
    voltage circuits of any amp should be a MIN of 2-watts.  The screen
    resistors across the power tubes should be 5 watt min.  Any cathode
    resistors on power tubes should be 10 watt min, 25 is better, as they
    handle alot of heat.  Any resistor supplying B+ voltage to preamp
    tubes should also be 2-watt. RCA & ECG makes great 'Flameproof'
    units, about 75 cents each, that are very quiet.  Never use
    carbon resistors.  Wirewound resistors may seem the best, but
    only non-inductive units should be used, because otherwise they
    act like coils, and change the sound.  This is ok for caps, but
    not in tube signal paths/areas. Remember, resistors have their
    own sound, very much like tubes do.  
    
    NEWS: KittyHawk may never get off the ground, due to lack of $$$,
          and not lack of interest.  Japan has no interest in KH.
    
          New Orange amps will arrive by the Jan NAMN show, built to
          the same specs as the UK units, & now made in Japan.  They
          will not have the Partridge transformers ( the same used in
          old UK Hiwatt, Orange, and OLD Laney) though.  Partridge
          (now out of business) at one time made the BEST transformers
          around.
    
          Now that Japan can't have Boogie, watch for a new company from
          Japan to compete Head to Head with them, in looks & features.
    
          
          Watch for new Sundown amps.  They are made by the same generic
          "design for hire" company that makes Jackson, the new Hiwatt,
          and a few others.    Hope they are better then the old ones.
    
          They would have to be.
    
          More fuel to the Ampeg fire...a sealed bid auction was done
          for the remaining stock of power & output transformers for
          the tube amps.  The above generic company bought them.
    
          
          Jay
    

    Just a quick reminder, any mail sent to my P.O. box without a SASE
    cannot be answered.  I don't mind copying things for folks, but will
    not pay postage to do it.  Please, I am poor enough as it is.
    
    My stock of 12AX7As is empty now.  I will have more within 5 days.
    
    Hint: Only 7 schematic/catalog packs left.
    
    Rumor:  The new Gibson amp will be a 1-12" NON- BOOGIE style, more like
            the old Gibson amps, one chennel, simple tone controls, but
            2-KT88/90 output tubes in Class-A.  I have seen & played
            thru a beta unit.  It kicks mean butt!
    
    Fact/Rumor: Gretsch will remake the western style amp, with the same
                features as the one pictured in the new GP centerfold!  If
                any of you do not have the new Gretsch catalog, order it
                today.  Well worth $2!  The new guitars are as fine as
                the older ones, in some ways better.  Fred Gretsch has his
                butt on the line in this venture, help him out!
    
    FACT:  Marshall will re-introduce the plexiglass style head and combo
           again.  Also, the 200 watt Marshall Major (4-KT88/90s).  And,
           no, my Marshall Fuzz/reverb unit (looks like a small head) is
           not for sale at any price.  If you find one around, I have the
           schematic, so BUY IT !!!! (good price: $300-$700)  It's great!
    
    Wanted: Marshall wah-wah pedal!  e-mail me!
            stupid money paid for right unit!
    
    Next post:  I'll give a list of *TRUSTED* used amp dealers who deal in
                old vintage amps.   LOTS OF BANDITS OUT THERE, BE
                CAREFULL!!!
    
    It's Sat morning, I'm going home...nite everybody!
    
    Jay
    

    Yo jay, question for you here:
    
    You said that a Marshall Major with the bias cut in half (or something
    like that) made the BEST 100wt Marshall head around.  Well, did you
    mean the the '67 Marshall Major's with the MV/active-Treb/Bass layout,
    or the '68 version with the dual channel, passive 4-band eq layout?

    Yo!  Yes, but there is more to the modification then that.  Send me a
    SASE for complete details.  By the way, if anyone has Marshall majors
    for sale (I WANT A 3-CONTROL OLD '67 UNIT NOW!) E-mail me with details!
    
    Here is a listing of "HI-TECH" preamp tube replacements.  The
    replacements are stronger units, with less chance of ringing in
    those hi gain preamps:
    
    12AX7A:                 5751         6681         12AX7WA  (China)
    12AT7A:                 6201         6679
    12AU7A:                 6189         6680         5814
    
    
    Also, here is a listing of trusted Vintage amp dealers I have worked
    with:
    
    Angela Inst.   Steve is the best around, has all the neat replacement
                   parts, and when he prints a catalog, folks save them for
                   the data. DON'T GIVE HIM A HARD TIME!  301-725-0451
    
    Dynamic Sound  Another good guy, with smarts & good prices!
                   203-753-9144
    
    Americian Guitars Center     301-929-8478
    
    Music Ground   In the UK, but they have everything.  Prices alittle
                   high by the time they get here.  011-44-302-320186
    
    I don't remember if they moved yet, but City Lights in N.J. is also
    great too.  Madmen, but super nice. MoJo Guitars in N.Y.C., the king
    of old playthings every one thought was not cool enough. They knew
    better.  SUPPORT ALL THE ABOVE!   Nuff said.....
    
    I'll be back later...
    
    Jay.
        

    Did you know:
    
    Schecter guitars is owned by old ex-Acoustic employees?
    
    Mighty mite (now JB Player) once made pickups for S. Duncan?
    
    Ampeg was once made in Japan?  Pure Junk!
    
    Groove Tubes is the ONLY tube source that tests the tubes in vintage 
    amps?  It's true!
    
    At one time, in the UK, every store had their own brand amps?  Orange
    was the most well known....
    
    Orange was made under 3 names?  Orange, Matamp, White (black covering)
    
    Jay
      

>          Now that Japan can't have Boogie, watch for a new company from
>          Japan to compete Head to Head with them, in looks & features.
    
    I hate to sound un-American, but that could be great news for us.  It
    just MIGHT force Boogie to compete by lowering their prices!
    
    Mike

    It could be good news for another reason. It would be nice to see
    the Japs get in the tube manufacturing business. Currently the only
    tube manufacturers are in China and The Eastern bloc. Perhaps this
    could remove the threat of not being able to get good vacuum tubes
    beyond the year 2000.
    
    Mark

    Yes, I know it would be nice for Japan to enter the Tube amp market, 
    but a few things would have to happen 1st:
    
    1: Some one in Japan would have to learn how to build output
       transformers. They import all of them.  Also, they have a different
       way of hearing things (how many good HiFi speakers come from Japan?)
       and this holds true for tube circuits.  95% of all tube circuits
       come from the US or UK.  Japan has NEVER built a successfull tube
       amp yet, the last were the MTI Ampegs. Even the folks who bought
       Hiwatt have them built in the USA. Ditto for the new Oranges.
    
    2: Japan would never get into the tube manufacturing business, to do so
       would need mucho tube building equipment & China has all the GEC
       gear, ECG won't sell theirs, and the Eastern Bloc always had theirs,
       although it's in VERY bad shape.   No one designs new tube building
       machines.  I just cannot see it happening.
    
    Don't worry, we will have tubes past year 2000.  Between HiFi, Musicial
    instruments, and the like, the need for tubes has not been better in
    the last 10 years.  These other companies have invested big $$$$$$$$$
    $$$$$$$$$$$$$$$$$$$$$ into tubes, they will get it right.  New models
    to replace old ones (KT90 for example) will keep it going.
    
    Remember this, solid state suks anyway.  Live by this rule.
    
    Jay
    

    So far, all of our discussions have centered on Guitar amps, and
    (to a lesser degree) bass amps.
    
    How about tube "sound reinforement" amps, for home stereo and PA
    applications ?
    
    My understanding is that the Grateful Dead used to use MacIntosh
    MC2300 power amps in the PA system they were using around the late
    '70's early 80's. Were these tube amps or SS ? MacIntosh used to 
    make tube power amps, but I think they have gotten out of the tube
    amp business. Jerry Garcia still lines out his Twin reverb to a
    MacIntosh tube power amp. He definately gets a nice sweet sound out
    of it. He drives the Mac into a cab with 3 12" JBL speakers. I wonder
    if the amp is stereo, mono, bridged, or what.
    
    In an old amplifier note, someone mentioned a 50's vintage tube amp
    with a built-in compressor (implemented with tubes, of course). I
    would think a tube compressor would have a nice sweet sound, but it
    would be rather tricky to get it to work well without being noisy.
    Someone mentioned a company named "Drawmer" that used to make studio-
    quality "tube" compressors. Jay, are you familiar with these units ?
    Do they really cost "thousands" as some people have suggested. Have
    you ever seen a circuit for a tube compressor ? I am mostly interested
    in a "sustainer", as appossed to a limiter. It seems to me that you
    could make a really great one with tubes, but no one does, that I am
    aware of. Maybe I'm wrong, but I would think that something like this 
    would sell (I certainly would be first on the list to buy one).
    
    Is anyone familiar with the Mesa Boogie Strategy 400 power amp. Mesa
    claims you can run it with all 6L6's and use it as a sound reinforcement 
    amp, or replace two tubes with EL34's and use it as a guitar power amp.
    
    I guess I opened a real can-o-worms with this note. Hope it jumps-starts
    the discussion. 
    
    Mark
    

    Nuno uses a Macintosh power amp and an MP-1...definitely gets a sweet
    sound outta it!!!

    
    Mac is kind of unique in that they are essentially a hi-fi firm who
    ahppen to build gear rugged enough for PA use.  The kind of power
    that's routine in solid-state (Crown actually has some amps in the
    kilowatt ranges) are nearly impossible in tubes.  Look at the Strategy
    400 next to a Crown MicroTech 1200 and you can see what the problem is,
    size and weight (not to mention maintenance) are stacked against tubes.
    
    For home stereo, there's still lots of tube stuff floating around. 
    There are dealers who cater strictly to audiophiles who insist on
    tubes, and they stock esoteric brands that still make tube gear, as
    well as used tube gear and even *modified* tube gear.  There's even a
    manufacturer in CA who has a tube CD player (obviously, only the analog
    portion is tubes, eh?).  Most of the hi-fi tube amps are low wattage,
    under 100 watts.  In the days of tubes, large, efficient speakers were
    the norm, plus, the warm clipping of tube amps is pleasant to the ear,
    so the kilowatts of power used to guarantee adequate headroom in
    solid-state amps isn't as much of an issue.
    
    There are notes in DSSDEV::AUDIO about tube hi-fi gear.
    
    							Brian

    Van Halen supposedly used a Variac on his Marshalls; some of the
    stories say he used it to raise the voltages in the amp, others
    say he lowered it.  Which (if any) is true?  What are the effects?

    Ritchie Blackmore got a very smooth "violin tone" from his modified
    Marshall Majors.  Despite all the technological advances since then
    it's tough to recreate that sound on a modern tube amp.  What's the
    secret behind the Blackmore tone?

    Van Halen definitely RAISED the voltages on his Marshall tops via a
    variac.  I have him quoted here in an interview saying he used to 
    crank the voltage anywhere from 400 - 600 volts!!
    
    RE: Blackmore...Marshall still says that the infamous "Blackmore mods"
    were no more than MV installations!

    Hello, here is some ideas:
    
    The Mac power amps used by the Dead were Solid state. Great amps!
    
    The Mac 70 tube amp from the preamp of a Twin is a common mod.
    
    VH raised them and burned out 3 transformers a night.
    
    The Blackmore Major mod was just the MV, and Gold Lion KT88's
    They were boosted in B+ to the tubes limits, and rebuilt to spect 
    to hold that power.
    
    The best vintage UK tube amp buy is a 100-200  watt PA head.  Great for
    guitar & bass! 
    
    
    Gotta goto work......
    
    Jay
    

    There are alot of unsung heros out there that are great buys:
    
    Plush 800G 6-KT88's, 300watts rms, and transformers that would of cost
    $$$$$$$$$$$$$$$ today.  Strip the pading, and you got yourself a buy.
    cost then $999.00  today?: $200.00
    
    West 'Filmore', real dogs, but loud and used 4- KT88s.  Can be had
    cheap, cause no wants to sound like Grand Funk (which were Marshall's
    anyway).  I have schematics, if you need to fix one.  Cost then:$800,
    today? : $200
    
    Any Sunn tube amp.
    
    Ampeg V4, V2.  The Magnavox 'weird' tubes cost $$, but because of this
    you can buy heads for $75 and up.  VT22, VT40 cambos are good too.  
    They sound great.
    
    As far as tube compressors go, I have a few 'home-brew' ideas from old
    books, but few have been successfull.  They are just units with tube
    diodes.  I'llhunt down some schematics, and get back to ya.
    
    Fact: the famous Park 75's were more or less 100 watt Marshalls set to
          use 2-KT88s, not 4- EL34's.  I'll go into the details to do that
          watt Marshalls in a later note.
    
    Jay
    

    1st off, sorry for my spelling and spacing in my notes, it is 3:30 am.
    
    Kitty hawk amps were sold mucho cheap, and there are many out there
    used for around $300 (M3 heads)  Some need work, some tubes. Check
    your starving music store for the ones with dust on them, make a offer.
    
    I need a little feedback?   
    
    Does anyone think there is a market for High end 19" rackmount, all in
    one Tube guitar/bass amps?  Just simple 1-channel, with balls,  without
    90 controls?  Any ideas what you would want in it?
    
    The Park 75, like the red one mentioned in the GT tube book, was a 100
    watt Marshall (who built Park) using 2- KT88s, not 4-EL34s.  B+ voltage
    was boosted, and since it only ran 2 tubes, current was high.  Also,
    the negative feedback resistor was removed. This produced about 85
    watts rms, with alot of crunch. This can be done, with changing a few
    voltage parts, removing the NF resistor, and using 2-KT88s.  If someone
    would like the plans, e-mail me, or send me a sase with request.  It 
    can be reversed, and I think it can be switched in/out, but not
    'on the fly'. What a monster!
     
    BTW, Peavey is a great source of tube amps to modify.  The transformers
    are no big deal, but many things can be tried.  Cheap $$ too. 
    
    Fact: Replacement Fender transformers are so hard to get, folks are
          striping 2 Twins to get one.  Ampeg (older) the same way.
    
    Till next time....
    
    Jay
    
    

    Waaaaaaaaaaaaaaaaaaaaaa...I want a Park head NOW!!!

      The Marshall Majors that Ritchie Blackmore used (and abused)
    were modified by Doc Stillwell who runs a shop out of Cortland,
    NY. You always saw Blackmore with at least three heads, two in reserve.
    Stillwell had quite a rep in the 70's as one of the first to be
    a hot-rodder of amps. The Lee Jacksons and Paul Riveras of today
    are probably a lot more complex than the early 'rods. 
      The Vox AC-40 I almost bought (should've done it!) was totally
    reworked by Stillwell. New tubes, capacitors, upgraded resistor
    wattages. But if it had broke, Stillwell probably wouldve been
    the only one that could've fixed it. 
      Hey Jay, we know all about the Kitty Hawk blow-out, it's all 
    in topic 1103.mega. Maybe one of these nights you should check 
    out the replies in it, hopefully when you're getting good response
    time. 
    
    							-BooM-

    Kitty Hawk M1's rule!  And I only paid $200 for it! ;-)
    
    Mike

    Alright, enough about KH.  For now.
    
    Here's an idea for preamp tube modification.  This involves no circuit
    change, but you must start with a NEW 12AX7.  This should work with
    fine results apon every preamp/driver tube, but shows best use on the
    1st tube stage.
    
    Remember when Boogie sold 12AX7's that looked like they were wraped
    in black tape, all the way to the silver coating on top?  That was used
    for two reasons.  1, to secure the glass tightly so it would not
    vibrate.  2, which was unseen at 1st, was to restrict the leakage of
    visiable light to leave the tube.  Hench, the flow of energy did not
    even try to leave the bottle, in whatever form, and remained stable
    and unchanging.  
    
    It was ok, but what if you went a few steps further?
    
    Here is the idea, I've tried it, it works........
    
    1st: Paint the glass of the tube, from the base rim to the level of
         silver on the inside of the glass, on top, with Hitemp orange
         racing paint.  2 coats are good.
    
    2nd: Take copper shielding tape, and cut enough to circle the same
         area.  Wrap it tight, solder a ground to the copper, with a good
         size wire.  Wrap tightly.
    
    3rd: Wrap this neatly cut area with silver 'Duck tape' or better yet,
         get some foam rubber or rubber tube to slip around it.
    
    4th: Install tube, secure ground, rock & roll.
    
    This is great for lowering ringing in those high gain preamps.  It does
    sound like alot of work, but it is worth it.  Tube life is 50% better,
    current draw less, and the tube runs quiet.  
    
    KT90 samples are here.  So far they seem to match up in strength.  I
    have a Hiwatt 400 runing night & day with them in it, so far with no
    problems.  Hope more come soon.
    
    Fact:  Remember the Alembic rack mount preamp?  The schematic for it
           is a exact copy of a Twin preamp.  The idea to patch one output
           the input of the 2nd preamp is what made the Alembic so good,
           but the same can be done to a Twin preamp stage with a little
           work. And remember, use 12AX7's with yer Fender for more
           punch.  Never use 7025's.
    
    Rumor: China is now working on another 12AX7 type tube!  The beta spec
           sheet calls it a 20AX7WA.  Watch for it.  It drops in any 12AX7A
           slot, and lasts much longer, runs on higher B+, and has higher
           gain than the 12AT7!  Yes, there will be 20AT7 and 20AU7 (s).
    
    That's all for now.  More tonight.
    
    Jay.
    

    Sounds like an interesting idea, but I have a couple of questions.
    
    1) Why orange?  Does it make a difference?
    2) What exactly are you wrapping with Duct tape?  If you're wrapping
       the tube, won't the tape melt?
    3) You said this would increase tube life?  Aren't there heat
       disapation problems?
    
    Thanks,
    Greg
        

    I have a question, too. Are you saying to wrap the tube in copper
    foil, then solder a wire to the foil ? Wouldn't that tend to crack
    the glass ?
    
    Mark
    

    	I have a question and comments for (re: 71). About the light
    	that leaves the tube, are you talking about the filments?
    
    	Isn't most of the filment energy leaving the tube in the form of heat, 
    	which is boiling the electrons off the filments?  I don't use 
    	electronic gear except for recording and playback, and I have 
    	played with tubes since I was in high school.  On my tube recorders, 
    	they have medal shields that are grounds over the tubes and make 
    	it quiter.
    
    	I have seen people use heat-shrink tubing and heat-shrink tape to 
    	dampen the tubes so they don't ring when you tap on chassic. They
    	would cut the tubing to size for the tube, put it over the tube 
    	cold (important!) then let the amp cook, and shrink the tubing to
    	the tube.  I know that they now sell tube dampers, rings of sorthtane
    	(sp?) and in the audio amature magazine they ever have dampers to 
    	take away the excess heat.
    
    	Now a friend of mine who plays, says he tried to dampen the tubes 
    	but found the head amp didn't sound the same.  However, on his tube 
    	preamp and amp for his hi-fi he says it sounds better.  
    
    	I read about this conference in Audio notes, and I love tubes, so
    	I been following along, real interesting reading!  Keep them notes
    	coming.
    
    				roy
    
    		
    

    Where is AUDIO these days. I tried to access it @ DSSDEV::AUDIO,
    No one home.
    
    Mark
    

    
    Re: .75
    
    Try VAXWRK::AUDIO.  Hit KP7 to add to your notebook.
    
    						Brian

    1: Orange is the color it comes in.  Nothing else.
    2: Yes, it might, but it stays on.  Pre-cut high temp tubing costs
       money, so folks tried tape.
    3: No, the orange paint is made to handle high temp racing engine use,
       far more then the tube will produce.  Remember, all tubes like to 
       run 'hot'.  This is what makes this idea work, because the heat
       does not heat up the glass, but is retained in the bottle.
    
    It's not the wheel, but it does work.
    
    Jay.
    

    By the way, folks years ago used to dip tubes in melted plastic and
    or blow glass onto the tube to increase bottle thickness.  
    
    Preamp tubes like hot heaters, this is a reason folks run them at 12.6
    vdc instead of 6.3 vac.  Building up heat in 'heaters' forces the
    tube to run hot.  
    
    more later...
    
    Jay
    

    Before you write, I know the fore-mentioned new 20AX7A tubes goes
    against the numbering of the 1st 1 or 2 digits being heater ratings.
    They are claiming that the heaters will run up to 20 volts DC, yet be
    replacement parts for 6 & 12 series.  We'll have to see.
    
    Alot of folks have talked about using op-amps as drivers/sources/etc
    for tube preamps.  I have found few  to work well, and most just bog
    down the tube from doing what it's made to do.  Every company has had
    a tube/transistor design, a few are doing tube/MosFet/transistor
    units, but mostly tubes like to be run with tubes.
    
    BUT...how do we get a good sounding line-out without adding some
    op-amp circuit?  Well, a small transformer works fine, be it a bit
    noisy.  So, next day, I'll show 2 simple line outs, one using just
    resistors, but still giving a balanced cannon out, and the other that
    will use SOLID STATE OP-AMPS (there, I said it..) both coming from
    tube circuits.
    
    Oh yes, you must solder the wire to the copper tape before you apply
    it to the tube.  This is also true if you bridge them from one tube
    to another.
    
    NEVER try that mod with power tubes.   NEVER, NEVER, NEVER!
    
    Also, next time....Triode from Pentode Output tubes...$.50 a tube.
    
    Jay
    

        So if  I  understand  correctly, tubes run `better' when they
        run `hotter' ? (Unlike solid state ?)
        
        Matt

    The way I understand it is that tubes may sound better when real hot,
    but won't last...
    
    jc

    Tubes like to be run hot.  The worst thing for a power tube is to apply
    signal thru it without the heaters warming up.  Old tube rectifiers
    solved this, since there was a slight time delay before the B+ hit
    the power tubes, because the rect tube had to get warm.  The output
    tubes were always warm, heater wise, before signal arrived.
    
    Old tube computers always were kept on, never shut off, and their
    tubes ran forever.    Many home tube stereo freaks do the same.
    
    Now, here is how you can change the output tubes working design
    from pentode to tirode.  Why?  Well, as you have seen on some amps,
    a switch to do this.  This JUST moves the point of operation
    (pentode or triode) closer, not exactly, which would be hard to do
    by switch.  The REAL way is this:
    
    1: Shut off amp, let charge down, cool off.  Open cabinet.
    2: Desolder the wire to pin #4 on the output tubes.  Tape the end
       very well, i'ts "live".  Tuck away neatly & safe.
    3: Solder a 200 ohm 5-watt resistor from pin #4 to pin #3 on EACH
       power tube.
    4: Place back in cabinet, rock.
    
    This will give you about 25% less power, but will clip & crunch alot
    smoother.  Try it, you can always change it back.  Works on Marshalls
    or Fenders or anything.  Sounds best on Twins.
    
    Till Later..
    
    Jay
    

    Most preamp tubes are Triode, and purist in the HiFi world dream of
    power amps using a pure triode output tube.  6550s & EL34s & KTxx are
    pentodes made to run like triodes.  One of my fave-rave all time
    amps was this newer Twin, set just to Triode operation.  It only put
    out about 75 watts, but thru it's JBLs, it was amazing.
    
    I've also tried a Marshall Major, running Class-A & Triode in the 
    output stage. I still own the amp, and although it only puts out
    around 95 watts rms, it sounds like 4 AC30's stacked when run thru
    1 4-12" slant Marshall Cabinet.   Eats output tubes for lunch!
    
    Yes, Class-A bites into output tube life.  Real bad, say 35% less.
    
    Triode may extend life, but not by much.
    
    But what do we care?    We want good sound, not long life!
    
    Hint:  If you want a little more 'jazz' to your Marshall, over ride
           the 1st resistor to the preamp's 1st stage tube.  It should be
           47K-68K.  Effects may overload quicker, but if you re-adjust
           1st stage gain, you should have no problems.  This should
           help with a real weak pickup'ed guitar.
    
    Rumor: Ampeg might change hands again.  Talks and more talks about
           selling SLM/Crate/Ampeg as a whole.  To Japan again.
    
           Kustom should be in Chapter 11 as you read this.
    
           Will Ovation sell Trace Elliot due to QC problems?  60% chance!
    
           H. Peavey would give right 'nut' to own SLM/Crate/Ampeg, his
           only real enemy.  Japan dislikes Peavey because of his sales
           that eat into Japan's markets everywhere.  Japan want's amp
           company here in USA.  Japan would love to own Peavey (little 
           chance there).  They might buy SLM/Crate/Ampeg.  Can anyone
           see the writing on the wall?   More important...would anyone
           care?  A Peavey is a Crate is a Peavey is a Crate, right?
    
           No, Peavey makes better product.  Not the best, but many
           dealers would not be out there if not for Peavey giving
           credit when maybe he should not of.  Crate tries, but if
           this sale happens, watch the price war start!  
    
    Anyway.....
    
    Jay
    

    Yeah, I've had experience with bypassing the first stage input resistor
    on a Marshall (an old 50 watter).  This was told to me as a way to make
    Marshalls play better with Strats; works great.
    
    Question: can a 50 watt Marshall be converted to run with KT-88s (or
    KT-90s)?  I've only seen it mentioned here for the bigger amps, like
    Majors and the 100 watters.  Does it not work out on the 50's?
    
    Jay, could you give a little more detail on the difference between
    Class-A and triode?
    
    /rick

    Most of what applys to 100 wt Marshall mods does to 50s, except the 
    removing of input resistors in any amp with more the 2 output tubes.
    
    KT-88s in most cases, need to be biased much higher, up to -70 volts
    to run.  The KT-90 'should' change that, as it runs fine from -30 to
    -80 vlots bias, hench a drop in to most anything not a 6L6.  A nice
    touch is to run a 100 watt head, with 2 KT-88s only.  Since the head
    can produce enough current to run 4 tubes, running 2 hungry 88's is
    simple.  Trade off works out that at the stock '-44 volts' bias, 2
    88's draw just a little less then the head can produce, current wise,
    and it makes it.  4- 88's would be too much.
    
    I would not run out and grab 88's right now, the stock being built
    in China of KT88s is way poor.  FOB, at a 35% failure rate.  
    The ones that work, are great, finding good ones, harder then before.
    
    Market Quote:  Vintage Gold Lion KT-88s in factory box & ppd:  $150 ea
    
    Yup, used to buy them for $18.    Wish I did.
    
    Jay
    

    Class-A is the performance of operation of the amp, never switching
    on/off, but remining on Full Tilt.  Class-AB switches on/off like
    a crazy monkey, and that switching causes unwanted distortion.
    
    Triode is the internal design of the tube, having a differant number
    of screens inside to control (like a valve) in/out functions.  The
    triode has less screens then the pentode.  Alot of crazy prople do
    belive the triode distorts in a more pleasing way to the human ear.
    
    ONLY the Vox AC30 is a true Class-A amplifier at present time.
    
    I have set a AC30 to Triode operation.  Nice sounding, but not
    enough power to drive 2 speakers, so I disconnected one.  THEN,
    did that amp sing!.  5 days later, stolen from a truck.  Never
    say it again.
    
    Jay
    

    Just a few words on some new items I saw today:
    
    Power tube finned coolers.  A company in Canada sells these finned
    coolers for any output tubes.  They fit around the glass, and let heat
    be removed from the bottle area quickly.  Cost : about $11
    
     
    The same company also sells these retro-fit 9-pin preamp tube sockets
    that have rubber shock mounts!  They will not fit everything, seem to
    like PCB tube socket mounting (which is a real no-no) but do seem to
    work well.  Price is unknown at this time.
    
    These folks even go as far as to suggest forced fan cooling, thru pipes
    that cover the tube!  Gad, what will they think of next???
    
    Also:  To those who care, a large assortment of mail went out monday,
           so if yer waiting for a schematic or something, it's on it's
           way to ya.....
    
           The KT-90  samples seem to be holding up real well.  1st
           shipment of stock should arrive soon.  
    
    No news in the amplifier market of recent.  This seems to be the time
    folks are getting ready for the Winter NAMN show.  I will be there,
    and will post all the latest scoop here.  
    
    Oh well, back to work...
    
    Jay
    

    ohhhh..it gets quiet around here......
    
    Just a quick fix/mod for those who are burning output tubes faster
    then they can afford.
    
    On the plateof each output tube, where the primary output transformer
    connects, wire a 100 ohm/10-25 watt resistor on each tube, then connect
    the transformer wires back.
    
    This will catch any surges from the tube or the transformer and
    absorb them.  the higher the wattage the better.
    
    Works on any tube amp.
    
    Catch ya later...
    
    Jay
    

    oppps.....the last note ment to say:
    
    Attach one end of the resistor to the tube, the transformer wire
    to the other end of the resistor.
    
    sorry 'bout that.
    
    Jay
    

    
    I dunno, I never considered myself a tube man, but I'm in the process
    of rehabilitating another old tube amp and looked around and noticed
    that out of five amplifiers that I own, only one is solid-state.
    
    Maybe that's because I pick 'em up so cheap.  $10, $20, who can resist?
    8^)  8^)  8^)
    
    On to a question...what the heck is a 7199 tube?  It's the driver to the
    output stage in this Ampeg I picked up.  The rest of the amp is the
    usual 12AX7/6L6 setup.  Is this tube hard to replace?
    
    							Brian

    The 7199 is a dual tube, one part is a pentode, and the other a triode.
    
    The pentode was used to drive amp (voltage amp)and the triode as the phase
    splitter. And uses 6.3v for the heater.  Dyanco used in there St-70 and 
    Mark IV (120w) mono tube amp Hi-Fi amplifers I used to sell.
    
    Hope this helps.    
    					roy
    
    
    				

    The 7199 is a tuff one to find.  I'll check if there is a replacement
    for it around.  That was the trouble with the old Ampegs.  Odd, TV type
    tubes.
    
    I have found a company that has KT90's for sale, it's called VTL out of
    Calif.  $40 each is a bit of money, but I have found the KT90 the ONLY
    tube to replace 6550,EL-34 and KT88 tubes with.  30% increase in power,
    no bias adjustment needed most of the time, and they look like they are
    built to last.  About twice as wide, 1/2 taller then a EL34, but fits
    most unit's I've seen.
    
    If I find a lower price, I'll let you know.  Lowest price is $30 ea
    per 100.  If anyone needs a spec sheet, email me.
    
    Jay Tashjian
    

    Audio Advisor has the 7199 for $35 each, they also sell there own brand
    of tubes and the VTL brand. 
    
    There price for the VTL's are (each):
    
    		EL-34/6CA7  $20.00
    		807	    $20.00
    		KT-66/5881  $15.00
    		6550A	    $30.00
    
    	There toll free numbers are:
    				
    			in the USA: 1-800-669-4434
    		   outside the USA: 1-800-942-0220
    
    	There address is:
    
    			Audio Advisor,INC.
    			225 Oakes, S.W.
    			Grand Rapids, MI 49503
    
    The best prices I've seen on tubes was from Westinghouse, I don't
    know if there still in bussiness. I'll try and find out and post it
    here if they are.
    
    					roy 

    ...last time I bought tubes (6 months ago maybe) Union Music had
    7199s in stock.
    
    Edd

    Re: KT90s
    
    The Kitty Hawk M1 has the bias switch for EL34s and 6L6s.  Would you
    leave it at the EL34 setting for KT90s?
    
    Mike

    
    	Without anything plugged in, and the volume knob on 3,
    	anybody know what makes a ~20 yr old Fender Twin Reverb
    	sound like eggs frying? It's pretty loud too, complete
    	with pops and sizzles.
    
    	Neal
    
    	

    	It could be a number of things Neal,depending on whether
    or not it's constant and if you can still hear an instrument through
    it?  If so it could be Power supply capacitors on the outside of
    the chassis covered by a metal pan. Or it could be a tube.....
    
    						Rick
    

    Just a few thoughts:
    
    1: Westinghouse has not made tubes in years, and when they did, the 
       tubes they made were very bad.  Avoid them.
    
    2: The problem most likly is power supply caps on the Twin.  ANY
       Fender that old should have the caps replaced.  You can use any
       value from 50-200uf/450wvdc.  The 500 vtdc caps that were used when
       it was built were the only ones available at the time.  Replace ALL
       the filter caps at the same time.  Check to see if the caps safety
       plugs are popped.  VERY common in Fenders!  Replace the Bleeder 
       resistors when you replace the caps.  2-watt units only!
    
    3: In the KH amp, KT90s should be set for the EL-34 posistion.  You 
       MIGHT try the other, but the strain on the power supply might
       be too much, causing hummmmmmmmmmmm
    
    Jay, now going back to the grindstone...
    
    
         

    I've been trying a new idea on a few old junkers laying around, &
    thought I'd relay the scoop....
    
    If you look at any tube amp, there is always (save for a few, like
    my fave-rave, the VOX AC-30) a resistor coming from the poweramp
    driver stage (or there around) to the output taps on the output
    transformer. This is for "negative feedback", a reintroduction of the
    signal to the amp, to cure a few woes, and make the amp more stable.
    
    On Marshalls, look at the schematic.  Almost always, there are 2 values
    given for this resistor...100k & 47k.  One is for UK, the other (100k)
    for the US.  Thus, the US has1/2 the ratio of feedback.
    
    I SAY: remove this resistor.  I've yet to find an amp with good tubes
    that suffers from this mod, and I have found that at lower volumes, 
    the amp has a little more 'grit', or as some say, 'crunch'.
    
    DO NOT DO THIS WITH THE AMP ON!  If you like, you can go back and forth
    WITH THE AMP OFF!!!!  Maybe tommorrow, I'll try a switch that will
    allow ya to switch on/off.  I don't think it's needed anyway.
    
    Try it, you may like it.   I do.
    
    Jay
    

    By the way, on Fender Twins, the NF resistor is 820 ohms.
    
    I tried a Twin with KT90 tubes, and was amazed how much louder it got,
    not only a la crunch, but clean too.  I had to raise the bias a bit
    but other then that, it's a drop in.  
    
    This "KT-TWIN" put out over 150 watts RMS (so my scope says) and 
    makes them EV speakers scream!  I've loaned it out this week, so I'll
    have further scoop this weekend.
    
    Did the same thing to a Bandmaster head.  God almighty, it sounder like
    a Twin!  Barely fit in the cabinet though.
    
    I'm not involved in the marketing of the KT90, nor do I plan to any
    longer offer tubes for sale, but anyone retubing a amp (of any kind)
    who does not try these tubes is a fool.  Look for ALL the new amps
    coming out to use them, and soon the prices will fall!
    
    I cannot say enough about the KT90. I'm ordering more this weekend.
    
    Jay (again)
    

    Jay,
    
    	Are you saying the KT90 can be dropped into any Twin and the amp
    will run right with a minor tweak to the biasing ?? If so, could I
    make the adjustment in bias from the test points on my Fender "The
    Twin" amp ??
    
    How soon do you expect the price of these tubes to drop ?? 
    
    Mark

    My old silver faced Twin seems to run ok.  I might change the screen
    resistor to 1k in the long run, but it does seem to work.
    
    It does make the amp a different animal.  You may or may not like it.
    
    Has anyone read the Amp issue in GP? Any feedback about the 'Bassman'
    & clone review?  
    
    Contary to print, both Russia & China are building good tubes.
    
    ""   ""  "" "" ", Tube sales are better then ever.  THIS is why other
                      companies build tubes.
    
    ""   ""  "" "" ", Tanks do not use Tube radio equipment.  Not ours
                      anyways.
    
    Jay
     

    After talking to my source today, and ordering some KT90s, I was 
    informed that prices will NOT drop till after Jan/91.  The $40
    single price can be lowered to about $28 if over 100 units are
    ordered.  VTL seems to have a lock on them 1st, then others get
    them.  After March/91, Ram tubes will control the numbers.  I have
    no idea why they are sold this way.  My source in Canada gets them
    directly from the source.  He is working on a big order to offset
    prices, down to $20 ea per unit, singles.  Compared to the price of 
    other tubes, this is not so bad.
    
    News:
    
    Rack mount single channel tube amps will be the rage this NAMN show.
    Expect one to even have a MARBLE faceplate!!??!!  Tests of this unnamed
    unit showes 100 watts RMS with !2! KT90s.  It screams!
    
    Ampeg will STILL drop tubes in 1991.  Ignore the ads.
    
    Mesa/Boogie will sell solid-state power amps.
    
    PRS amps will die a QUICK death.  QC problems.  Solid state too.
    
    Fender will introduce the White covered "Twin" this Namn.  Also, they
    will have the frames of the speakers brown JUST like the old ones.
    
    Next Note?  Results of KT90s in an old SVT head......
    
    Jay
    

    After placing $300 worth of KT90s in an SVT head with great results.
    
    Thru the stock SVT cabinets, it was good.  Tighter bass, and about 500
    watts RMS.  Thru 2 V4B cabinets, it was deafening!  Way too loud, but
    very tight.  BUT, I have 4 V4 cabinets with old Altec speakers.  Not
    only did it make a nice looking stck, but was way louder then you could
    belive. The head has a MV, and was needed to control everything.  
    
    Next, I'll tube up the other SVT head and make a double stack.  Far
    more then you would ever need, but a nice idea if ya got money to burn.
    
    Lowering the bias to convert to Class-A helped, but the amp was
    unstable, heat and hum being too much.
    
    Anyway, I did keep one head stocked this way.  Ya never know, I may 
    have to play Foxboro......
    
    Jay.
            

    I know the GP Bassman review was discussed elsewhere, but I can't find
    the note (I tried, honest).
    
    First, I thought this was a great way to review stuff; it's an
    entertaining idea, and they didn't wuss out like GP usually does on
    product reviews.  Let's see more articles like this.
    
    I learned two things from the Bassman shootout; first, the speakers
    more than anything seem to be the secret to the Bassman mystique.  For
    all their fancy, expensive attempts to recreate vintage electronics, it
    was the speakers where the two non-Fender clones made the most
    compromise.  My guess is this is why the Fender clone sounded most like
    a "real" Bassman to the panel of experts.
    
    Second, don't buy any Fender clone stock :-)
    
    Since the re-issue Bassman seems to have turned out so well, I'm looking
    forward to checking out the upcoming Fender Vibroverb and White Twin
    re-issues.  For anyone who's interested, here's a couple of prices from
    a vintage shop flyer I got recently:
    
    1963 Vibroverb (same as one being re-issued)	$2000
    
    1957 Bassman					$3000
    
    Btw, the '57 Bassman is not even the most "desirable" version of this
    amp.  It has two inputs (vs four on the '59) and doesn't have a MIDDLE
    control.  Yowza!

    What is the differance between the Vibroverb, and a Vibrolux ??
    A friend of mine bought a 1965 "Black-face" Vibrolux (in perfect
    condition) in Boston for $450. That'll be the day I would spend
    $2000.00 for one.
    
    Mark

    CAN YOU BELIVE IT?  $2k for an amp like that?  Even the 'clones' at
    around the same price is crazy.  Even at $700 list, one has to ??? it.
    
    The speaker is a VERY importat part of any amp.  The SVT is not the
    same without the 16-10" speakers, a British stack sure changes if
    you put JBLs instaed of Celestions in, and even the rare "Delta" 
    tube amp sounded like shit without the 4-12 & 2-10 cabinet with
    the cheapest speakers around.  
    
    I think we are all being taken to the cleaners on these 'Vintage'
    amp deals.  I'd rather buy used.
    
    Jay
     

    The Vibroverb with 2x10s was only produced for a short time in 1963,
    making it rather rare.  Plus it was the only brown Tolex/panel Fender
    amp to have reverb.  Brown Tolex Fenders (white ones too) were noted
    for their tremelo circuit, which was more warbly than the one in later
    blackface amps.  Thus the Vibroverb was the only amp to have both
    reverb AND the cool old style tremelo.
    
    Fender also made a later blackface version of Vibroverb with 1x15;
    these are not anywhere near as hot collectors amps as the browns.
    Stevie Ray was a fan of 1x15 Vibroverbs and used to use a couple
    until they were stolen.
    
    The Vibrolux Reverb is a blackface amp with 2x10s.  It's probably
    very close to the brown Vibroverb, except for the tremelo circuit.
    $450 for a very clean blackface Vibrolux Reverb is, sadly, a bargain
    these days.

    Those old Fenders are quite collectable today.  There were many Ma & Pa
    shops that were Fender Dealers (I remember a Stop & Shop up in Maine
    that was a dealer) that were LOADED with black-faced Fenders, selling
    out as low as 30 cents on da $.  Anything that wasn't a Twin or Showman
    didn't sell in these shops.  Wish I had the $$$ then.
    
    Vox (Thomas Organ units) was the same way.  They would open ANYONE
    as a dealer (on such shop in Mass. was also a Fish & Chip shop) &
    when the line went belly up, as many of the fish shops did, the
    'dealers' ended up keeping the stock, and selling it cheap.  I bought
    2 of my 4 Super Beatles that way.  Showroom stock, with covers, F/S &
    stand for $400 ea.  Value today?  $1k each.  
    
    But, back then, to be a Marshall dealer, you needed $5k in opening
    order, had to take on the dreaded 'Univox' line of amps, and pray
    you could sell them cheap enough to fight NYC.  Does anyone remember
    those gawd-ugly blue Univox amps?  The !ONLY! one worth poop was the 
    UX-1001 with a 6-12" cabinet.  It was a 4-EL34 output stage, but the
    preamp allowed ya to gang one into the other, thru a switch they marked
    "TUNNEL".  As one member of Led Zep said.."great sounding till they
    blew up, then out came the Acoustics..."  But, it has to 'rank'
    as the most ugly amp made.  Used by Led Zep, Jeff Beck (who endorsed
    Plush, which tells a story in its self.) and "Sugarloaf(?)"
    
    I have the schematic, if anyone dares admit they need one....
    
    What's next in amp re-issues?   Rebirths of companies?
    
    Rumors (belive it if ya dare):
    
    1: Plush will come back, as will Earth, with peavey clones.  The Earth
       units were 1st made when someone copied Peavey PCBs.  Lost a lawsuit
       but gained some history.
    
    2: EMC will return with the Zodiac series.....
    
    3: Fender will sue EMC because they want to re-issue their Zodiac
       series of SS amps, with the dreaded "Super Dual Showman" leading
       the way.
    
    4: After buying the name & remaining stock for WEST amps, Grand Funk
       Railroad will re-form to sell amps, not records, on the road.
    
    5: Disco will return, and Kustom amps will be there, roll & pleate 
       padded cabinets & all.  Plush & Earth will join in.  Peavey will
       try to R & P too, and fail.
    
    Just another night...
    
    jay
    

    Re: .109
    
    I have always wondered if Plush and Earth were one and the same...the
    first Earth units I saw were tuck and roll clones of the Plush heads. 
    Then they started cloning Peavey (why, for heaven's sake?)
    
    						Brian

    a side note re: Earth
    
    I remember when I was a young pup (foolish, to boot [cuz I sold off the
    following]), ;^(  I had a 69 SG with PAFs and "matching" 69 Marshall
    100wt "plexi" top with two 25wt-loaded cabs (these were the old cabs
    from Britton that just said "100" in the corner).  I was setting this
    mutha up for a gig once, and this guitarist walked in and barked
    "Bah...Marshall...I have an Earth amp that will eat that stack for
    breakfast!"  and I said "Oh yeah?"...turned all the controls up to 10,
    flipped the standby switch off and cranked out some super crunch
    chords.  Nuff said!  ;^) 
    
    So, how good WERE Earth amps anyways?
    
    B.

    You SOLD a plexi head ?
    
    <insert image of Coop shaking his head like Al from Happy Daze>
    
    Oh Buck, Buck, Buck...
    
    I'd give my yaaa-hoos to have a plexi head.  Whaaaaa...
    
    jc

    What's even worse is I tore the PAFs outta the SG and tranded em with
    some dude for two DiMarzio Dual-Sound pickups!!  ;^(
    
    Hey, I was 14, ok?

    It would take a home in La Jolla, CA for me to give up my filberts.
    
    Mike

    Can anyone identify the amp used by Santana in the movie Woodstock?
    The head is very flat, so it definitely looks to be solid state, and
    from the side view looks like a flattened hexagon (i.e., the front
    and back panels have two surfaces that meet at a point).  The bottom
    is black tolex (maybe grill too) with an orange logo in one corner
    that I can't decifer.  My immediate guess was Randall, but no pictures
    I've seen since of old Randalls match up.

    Your description reminds me of the Ampeg I had around the same time
    period as Woodstock.
    
    Chris D.

    
    	Woodstock?
    
    	Heh heh ... I was still in diapers then.  8^)
    
    							GTI
    

    That amp was a VERY early GK model, back when they were known as
    GMT.  A very rare amp, but the same guts as the old GMT G-500/300
    Metal heads that Traynor copied.  I belive new GK stuff is nice
    but a PAIN to fix, everything being so small inside.  But, that pointed
    thing is a GK.
    
    Earth & plush were the same amp.  Earth Peavey clones were cheap, &
    the story about the PBC copying is true.  Plush Tube units were
    Kustom clones, and they were OK.  Now a days, they can be had cheap, 
    and make great sources for 'good' transformers and are great 'project'
    shells.  Remember, alot of Kustom cabs were sold with JBL & Altec
    speakers.  Many a Padded cab I've bought for $75 had 2 or 4 JBLs in 
    them. And ANY old beat up VOX cab, Us/Uk (Usuck?), had Bulldogs in 'em.
    
    
    Gotta go ta woirk...
    Jay
    

    Another example of a early GK/GMT amp is on the inside cover of
    F.Zappa's "Roxy" LP.  I sold him that amp for $200.  Traynor later 
    copied that look for their dreaded "MONO-BLOCK" series of poop.
    
    Japan has copied Peavey too.  They made some nice units using that
    "Peavey" look (for want of a better name).  They used to copy tan/white
    Fenders too. Under 100's of names.
    
    Japan has copied everything in amps, even some horrid Kustom padded
    PA systems.  They mostly copy looks, and in many cases improve
    the guts. 
    
    So we see, clones are not new, but most are/have been rip-offs....
    
    Jay
    
    
    

    While we're on the subject of weird amps, remember "TUSC" ?  By old
    Ampeg employees, who started a medical equipment company?  Gad, 
    another slice of dog poop.
    
    How about 'VAMP', 'Oliver', 'ARB', 'GBX', 'ORBIT', 'POON' (YES, POON)
    AND OTHERS?  REMEMBER 'AXIS'?  These and many others beasts will be 
    talked about in later notes.
    
    Now a ???   Who was the other padded amp builder?  Not Plush, Earth or
    Kustom.  Any Guess?
    
    How about, who made the most ugly stack ever?   how about a few
    entries?
    
    jay
    

    Well, since they got me working Sat Nite, I thought I'd enter
    some more.  Bored ya know.
    
    1st off, a hint on the padded amp ??.  It was shown all the time on a
    TV show, and the 'group' who used them were quite popular. The amp line
    is no longer made. The company who made it still is around.  Hint Hint!
    
    
    Anyway, 'ARB' made guitar/bass amps in the 70's, not bad units, but
    ugly as sin.  They are more famous for the PA cabinets.  2-15" sp on
    one side, 4-EV horns on the other.  The ENTIRE cabinet & the horns
    were 'Flocked' like wallpaper with fur.  The only units I ever saw used
    by pros were the PA cabinets used by F. Zappa. You can see them in the
    movie "200 Motels" (a great flick).  Now, ARB is QUITE dead.
    
    And 'VAMP' was a UK company, whose only claim to fame, is M. Bolen of
    T. Rex used their stacks.  One is pictured on the front cover of his
    1st LP.  Not a bad unit, just another Marshall clone, but VERY costly
    to buy in the UK, and none made it for sale here. VERY (!) RARE.
    
    'GBX' made those ugly SS units that looked like they came from Mars,
    with just preamps on top, and power amps in the cabinets.  Badly
    made, they never made it here, and were built in Canada.  Chas Bean
    music of Mass. inported them en mass, like they did Traynor.  I swear
    that chain bankrolled Traynor with all the amps they sold.
    
    The ONLY 'AXIS' I ever saw was the giveaway in GP.  The company folded
    right after.  What a dog of a stack. SS too.
    
    Next time?  The poop on 'Poon'.....And on Monday, some updated rumors
    in the amp world.  MAYBE we'll get into beefing up SS (solid-state)
    units, as alot of folks want to hear about chip IC updating.
    
    It'd 4am, Sat, and I'm tired.  
    
    Jay
    

    RE: Jay's mentioning of "OLIVER" amps...
    
    
    	When I was in high school (early '80's), a friend who played drums 
    also had an old "Oliver" head. It was about 75-100 watts, all-tube, and 
    looked more like a short-wave radio than a guitar head. I was playing
    thru a solid state Peavey at the time. Since he played drums, I started
    using his Oliver head, just for the heck of it. I paid about 3 times
    more for my Peavey head that he paid for this piece of junk, but that 
    damn Oliver sounded great. The tubes were going but it had the most awesome
    ballsy sound I ever heard. I used to crank it up & play Angus Young
    riffs into the night. Unfortunately, it got so bad that it was blowing
    fuses every 3 minutes on-the-dot, and you could watch the pretty blue
    bolts of electricity shoot across the back of the amp. My friend
    brought it to be repaired & they told him the tubes were totally gone;
    he had all the tubes replaced & it seemed to work fine afterward...
    but it never sounded as cool again. What a loss.
    
    	Now that I think of it, I believe we were playing the head thru
    Radio Shack 12" speakers. Yeesh, what a combo. But it did sound cool,
    though, even if it was only for a while. God knows why.
    
    	That amp was a real death trap. It did teach me 2 valuable lessons
    though... replace your tubes before it's too late (and you're still
    alive), and never buy an amp with the same name as a Broadway musical.
    
    
    
    Brad Page
     
    

    Yep, them Oliver amps were killers.  It seems they had such cheap parts
    inside, that with age & wear, they forced the tubes to burn out.  Bias
    droping, current raising was the 1st result.  Next, came the power
    caps.  I have 2 Olivers, and I tell ya, I've blown away folks who eat
    & sleep Marshalls.  Not many Olivers lasted thru the club circuit.
    
    Not many around now.  I see alot of the cabinets, beaten up to bits.
    
    "POON" was a small amp builder from Texas.  The stack they built looked
    like a monster, very large cabinets, real small head.  Solid state, but
    not clean, they lasted about a year or two.  Then, lack of funds,
    blah, blah, forced them out  Some of the folks started the "Legend" 
    brand of crap (Ugly cabinets, QC problems), others started to sell
    Real Estate.  A very rare amp, the last I saw was in the UK.
    
    Remember "Foxx"?  Built by VOX (True fact), but was solid state, they
    were dist by the Foxx pedal people, and looked like a AC30 (same
    cabinet).  Not a bad sounding amp, but few made it here.
    
    How about the "Mike Mattews Freedom amp"?  From Electro Harmonix,
    now Mike sells Tubes out of NYC.
    
    Ever see the "Simms Watts" amp used by David Bowie?  Blue speaker
    cloth, orange covering.  !*UGLY*!  But, the best sounding SS amp
    from the UK ever built.  VERY FEW ever made it here.  Look for it
    in the live Space Oddity video.  Can't miss it.
    
    
    Then from the UK came: Impact, Trucker, White, Carlsboro, Heyman, LOX
    (yes, LOX), and others.  EVERY music store built amps.  Few lasted
    over a couple of years.  Fewer made it to the US.  Only Marshall, Vox,
    Orange, & Hiwatt became household words.  Close seconds were WEM &
    Laney.
    
    One last ??   Did Marshall ever make amps on stands, like VOX?
    
    Till next time, 
    
    Jay
    

    The other padded amp line was the Ovation amps of the early seventies.
    Weren't some of them modular, using powered cabinets?  
    
    The TV show you mentioned was "The Partridge Family".
    
    						Brian

    
    	re .121
    	I remember GBX. I used to rent the GBX "pa" from Chas
    	Bean for $50 when we had a "big" gig to do. Gawd that thing
    	was awful. Good thing the speakers had circuit breakers, even
    	though we had to keep resetting them. I think it was only
    	75 watts.
    
    	Neal
    

    Back in the mid-70's, I ran a music store. One of the local "big bands"
    bass player owned a GBX, for a while. He was bringing it in to our tech
    on a weekly basis, and we'd always kid him about his "great" new amp.
    
    I don't remember what happened to the amp, but it probably didn't
    survive having all of the solder joints re-heated so often...8^)
    
    Bill

      The ugliest stack? I'm not sure if it qualifies, but I used to
    have a Sound City stack from hell that was fairly grotesque. It
    was all tube, had very versatile tone controls. Unfortunately
    it wasn't a great sounding amp overall. I think they used Fane
    speakers. 
      Hey B.R. - I think you're right on the "other" padded amp. I remember
    seeing the Ovation padded amps. They weren't roll n' pleat, more
    of a smooth padded cover. The Partridge Family used them? Now
    there is an endorsement for ya!
      Jay - One of the people behind the "Legend" amps was from Syracuse.
    I remember him showing me the prototype. It had a tube preamp and
    solid state power amp, but they billed it as a tube amp (the bastards).
    Even though the company started in Syracuse, the had their production
    out of the old Kustom factory in Chanute, KS. A lot of people in
    Syracuse had Legends, I for one. Trying to sell one in Syracuse
    these days is like "How much will you give me if I take it off your
    hands?" The cabinets make great firewood!
    
    							-BooM- 

    My vote for ugliest stack in recent years has to be the Metaltronix
    M1000.  That ugly copper front plate and the nasty looking matching
    cabinet...brrrrrrrr...
    
    To this day I'd have to say that it's one of the best sounding amps
    I've ever heard though.  What do you think of the construction and
    quality, Jay?  I'd heard they had reliability problems.
    
    Greg

    My ugliest stack vote goes to the 1976-78ish Carvin series amps.
    Butt f-ugly!

    I agree with something Jay mentioned earlier about buying used rather
    than going for something like the new Fender re-issues.  The problem is,
    old Fenders, Marshalls, etc. aren't the bargains they once were.  To me,
    an old amp is only worthwhile if it sounds great AND is cheap.  Vintage
    mania has pretty much eliminated a lot of the Fenders, etc.
    
    But, I believe there are still cool bargains in old amps to be found.
    Someone recently mentioned LAB Series amps, a primo example; well
    built, versatile, great sounding, and mucho inexpensive on the used
    market.  Jay, how about giving us some more recommendations, perhaps
    your TOP TEN used amp bargains to look out for?

    
    RE: Mike Matthews Freedom Amp
    
    	
    	I almost had one of these as my very first amp; I remember it being
    very small. I thought it sounded great then, but then again, I was
    still in Junior High & just starting out. I wanted to get it, but good
    Ol' mom & dad were spending the money, and my mom thought it looked
    ratty (it was a used one), so they bought me a "RAM" amp. What a piece
    of junk-- even I thought it sounded bad! Anyone else ever heard of RAM
    amps?
    
    
    
    Brad Page
    

    Yep, Ovation was the other padded amp.  Some of the worst made amps
    ever.  With names like "little Dude".  The coverings ripped fast, and
    it's hard to find units around in good shape.  Remember stores having
    stacks of 'dudes in the store?  Pure junk.
    
    GBX was a pile of poop.  Never more then 75 watts PEAK per cab, and I
    made big $$$ fixing them.  Finding them here is rare, but up north in
    Canada, they sell cheap.
    
    NO ONE wants a Legend.  At any price.
    
    I remember seeing Ram units, but never working on one.
    
     
    Sound City looked bad, but sounded great, and the big dealer in Medford
    Ma (Pampalone I belive) sold 1,000s of em.  Good transformers.  The
    "Tour" series head was great, Tube compression overdrive, & the
    output stage used 8 EL34s, 6 as outputs, and two as driver stages!!!
    
    Top 10 bargins?  Let me start with 5, 5 more tommorrow....
    
    (in no order):
    
    1: Lab L5.  Great amp, good sound, put better speakers in and
       use it anywhere.  Under $300 used.
    2: Ampeg VT22/V4.  Buy the tubes, play the amp.  A killer amp now sold
       cheap.  Under $200 w/o new tubes.
    3: Any Twin.  Find one with JBLs or EVs.  $300-500 used.
    4: Bandmaster/Bassman heads.  Great Fender sound, cheap price.  Some
       good cabinets.  Every mans backup amp.   $100-250 used.
    5: West heads.  REPLACE ALL TUBES!  You to can be GFR!  If ok, a great
       sounding HM head.  Cheap!  $100-200 used.
    
    Talk ta ya later...
    
    Jay.
    

    Jay:
    	Is there an alternative to the power tubes in an Ampeg V2. The
    price up here for 7027A's is $65. each. What else can be used and what
    are the mods to do it. Also what should the dc resistance be on each
    side ot the o/p transformer. My new used V2 is sick no o/p tothe
    speakers but it has o/p on extension amp jacks.
    
    			       				FJE

    What would cause an amp to take on an unusually bassy sound?
    
    Thanks,
    Mike

    
    
    RE: -1   ME!!!  hahahahaha, jest kiddin' Mike
    
    
    	Good question, I've been getting some weird sounding noises from my
    amp like theres a little bitty guy with a little bitty skill saw inside
    cutting plywood boards... he cuts a board then he stops for a while
    then he cuts another one...  I've been chaulking this up to RFI, but
    while yer answering Mike's question, Jay how about this one too??

    1st off, there is a 7027A to 6550 mod in the GT book, I'll hunt it 
    down & inform ya.  I do think you are paying too much for the 7027A
    and I'll find a better source for ya.  They sound best in Ampeg units.
    
    
    The itty bitty guy inside is the sign of bad ground &/or
    bad preamp tubes, or the power caps that feed the preamp tubes.  You
    might wanna check all inside grounds.
    
    Too bassy is the sign of bad preamp tubes, and/or the B+ resistor
    connected to them.  Check for bad coupling caps too.
    
    Jay
    

    Oh, I forgot, having output at the Pre-out shows it's a power amp
    problem.  Check all tubes, and the driver.  If it has NO output at all,
    it's most likely the driver.  If you do need output transformers, I
    have a few. Check the pre-out/power-in jacks, cause if they don't
    connect, you have nothing going to the output stage.
    
    5 more good buys?  here goes:
    
    1: Any tube Traynor head.  Ya might have to replace tubes, but they
       are cheap, and sound OK.  $50-$200 used.
    2: Guild Thunderbird head.   LOUD!  great for guitar or bass, or
       whatever.  Tube & strong.  $100-150
    3: Acoustic SS heads.  Those thin 75-100 watt units.  Cheap, and
       nice tone circuits.  $75-200
    4: Check out old Gibson, Ampeg, Gretsch and Danelectro combos, some 
       with up to 100 watts, 1-12 & Balls!  $50-200
    5: Sometimes the best upgrade is to but different speakers.
    
    Have a happy holiday everybody, I got 4 days off.  & a bottle of
    J. Walker Black with my name on it...
    
    Jay
    

    	I found the problem:
    
    	It was the impedence selection switch. A shot of Contact 
    Re-nu and it now works great. I'd still be interested in a cheaper
    source for those tubes. The only two sources in Ottawa (that's in
    Canada eh?) really hose you on their prices
    			
    					Thanks for the help
                                        	
    						FJE

    Jay:
    
    Your "big book o' schematics...." Do you still have some? If so, I'd
    be interested in having you send me one, out here in Colorado. I'd pay
    UPS, of course.
    
    Bill Message

    Wow, back from Holiday, and still alive.  Here's the hottest rumors:
    
    1: Ampeg STILL will drop tubes, but now by end of '91.  I think
       alot of ya could care less, but I get enough Ampeg hate mail
       as it is.  Na-Na!
    2: Gibson will be the next 'Vintage' amp builder, with re-issues of
       old 'LP' units.   Watch for !HIGH! prices.
    3: Gretsch will do ditto as Gibson.
    4: Orange amps are coming.  Things are going well on that project!
    5: P R S amps are having !!MAJOR!! QC problems.  Real stupid things,
       so BE CAREFULL buying them.
    6: Fender will reissue the "Showman" tan amp.  2-12, Twin type head.
       one of the all time great looking amps.
    7: TUSC 'may' come back.   Who cares?
    8: HIWATT by the time you read this, may be broke.  Japan has lost ALL
       interest in this line.  Nice units, watch for big discounts soon!!!
    
    Not much more to say, gotta get back to work. 
    
    Jay
    

    
    
    
    	Jay, have you heard that Fender will re-issue the vibroverb??  DO
    you think it will be a worthwhile amp??  Or another OK, but expensive
    thing like my super 60???
    
    	What's the other name for the output driver tube??   Is there
    another name for it???
    
    Steve

    If Fender keeps true to detail, any re-issue should be good, depending
    if that's the type of amp you like.  They BETTER keep the prices DOWN,
    and only Fender can do that, the other companies MUST sell high, due to
    high overheads.  Look for Fender to cash in on this market, as smart
    people were on their toes, seeing the demand for such items. Look at
    the other companies (Gibson, Gretsch, Boogie (of all people)) now
    selling "re-issue" guitars & amps.  By the way, *I* suggested to
    Fender they do this, back when they were owned by CBS.  THEY laughed
    at me, saying no one would buy them.  These were the days, when you
    wanted to 'talk' with CBS, you had to sign a paper to the effect that
    "...for ANY idea, the most CBS would pay is $2k".  The old days.
    
    The driver tube(s) are the ones nearest to the power tubes, most
    often a 12AT7A or 12AX7A, never a 7025.  If in doubt, check the
    schematic, or look inside the amp (CAREFULL!).
    
    Anyway, back to work.   
    
    Jay
    
    

    I have an old off-brand tube amp and would like to replace the
    power amp tubes.  It has a pair of 7868's.  Are these readily available
    anywhere?  Is there a more-common (or better performing) replacement?
    
    Jim

RE: .141

Steve,

Maybe the term you're looking for is "phase-inverter". Jay can
correct me if I'm wrong, but I think the power amp's driver 
stage circuit is sometimes referred to by this name.

Ron

    Jay, I just bought a mint Ampeg  B15-S with an Altec 421 in it for
    85.00 I set the bias to -58v and it sounds good, but since the tubes
    are original, I think I'd like to put in 6550's , a couple of 2 ohm
    cathode resistors and somekind of wirewound individual biasing pot. Did
    you ever post the schematic for that or the mosfet bias that you were
    talking about and whats a good starting point for biasing a 6550? I'm
    assuming this tube will have a punchier sound ( according to groove
    tubes). Also whose got the cheapest/best 6550's..I don't think I wanna
    fork for groove tubes as this is only a practice amp.

    DRIVER stage is alike to inverters.  I use the term driver, because 
    that is the main job, inverting can be done without drivers, but we
    are just spliting hairs.  Both terms are correct.
    
    NEVER sell that B15S!  They are quite rare today, and one of the all
    time greatest bass amps.  A steal at 85, but with a Altec.  You
    lucky Bas#$rd!  I think you have the bias too high.  Try about -48
    volts.  The Mosfet bias schematic is posted here, I don't remember
    where.  I'll look into the 6550 mod, and post tonight.  IF I WAS U,
    I'd keep it stock.  Find a dog to modify.  But then again, I have 
    butchered plexi-glass Marshalls, so who am I to talk?
    
    ECC sells a great 6550, but try the KT88 or KT90.  The 90 would be 
    great in such a amp.   I'll check into it.
    
    Jay.
    

    I don't mind some simple mods especially when I can un-mod them. One of
    my 7027's has his plates a little red, all the resistors are on the
    money and the red glow follows the tube when I put it in the other
    socket, so its time for a set 'o tubes anyway. My local surplus place
    has GE 6550's @ $24.00 each but I'm sure I can do better. What's this
    KT90..I'll have to review your past notes!
    
    Here's another local deal I ran into....a VOX AC-15 TB for $ 335. I
    thought this was a steal, but turns out it didn't have top boost...it
    was a bass amp with VOX fane 12" speakers and didn't sound that good so
    I traded it for a SWR redhead.
    
    My local music store "House of Guitars" has tons of old amps jammed a
    mile high in their back room we check it every week for new, broken,
    cheap arrivals!

    STARK ELECTRONICS here is Worcester has ECC 6550s which are KT88s for
    $19 each. You are right, the tubes are the problem.
    
    That isn't a steal on the VOX, as AC15s go for under $200.
    
    I've been to House of Guitars, and have bought from them, and found 
    them to be very fair.  I'm happy others have had good luck with them.
    
    I'll be back...
    
    Jay
    

    Are the KT90's alot more money than the 6550's and would they be worth
    the difference??

    Where is this "House of Guitars" located ??
    
    Mark

    KT90'S are from $25 to $40 each.In a B-15S the supply would not have 
    enough current to let the tube work at what would be the advantage
    between KT88s & 90s.  You should find the 6550C, the smaller 6550
    shaped like a Coke bottle.  It looks like a "baby" KT80 is shape,
    and has alot of the advantages of the 88/90.
    
    Jay
    

    Rochester, NY
    

    Thanks for the info....is this 6550c something I should buy from Groove
    or is there a cheaper place?

    I've said it before, GT sells tubes at about the going price, and
    cheaper (depending on ya dealer) then others.  The 6550C is from
    GT, VTL and a few others.  I think that will be the best choice, and
    should sound best in the amp.  By the way, a 6550C is to a KT88
    like a 5881 is to a 6L6GC.
    
    Another trivia ??:
    
    On UNIVISION, the Spanish network, the bands always use a odd brand
    of "stack", whose name starts with a "H".  Can you name it, and/or
    give info on it?
    
    While looking thru a old Rolling Stone, I saw an ad by Univox for
    the UX-1501 12-12" "stack".  There's Jeff Beck, with Led Zep named
    as folks using the beast.  Copies for anyone who asks, along with a
    schematic.  I WANT ONE OF THESE SUCKERS!  So ugly, they're stupid!
    
    I think I'll start a "Name the ugly sucker" contest.  I must have an
    old Kustom padded head around that would make a sick prize.  HMMMMMM!
    
    Ya, that's the ticket.  Name the on going list of ugly amps, & win
    one the most ugly SS heads around.    More info later.
    
    Jay
    

    Oh, man you're so cruel...
    
    The later series of tuck and roll Kustoms (the 150-250s) in blue or
    green sparkle were the subject of my wet dreams for many years.  
    
    The next blue sparkle stack I see is going home with me...
    
    						Brian

    If you really want a blue ine I think there's one @ the "hog" House of
    Guitars

    Those blue Kustom amps are what many of us wanted.  The one I'll give
    away is black, 200 watts, with "..all the candy..." ! The contest will
    start next week.  Watch for it....
    
    I must go visit the HOG real soon.  I need new toys.
    
    As far as Kustom colors went, 1st blue sparkle, then red, silver, & the
    ever rare gold sparkle are wanted men.  The rarest is the blue, with
    a 3-15 cabinet.  Inside they were built well for a SS amp, with some
    neat-o circuit designs.  And the binder of schematics makes a great
    book for the coffee table.  I hope Kustom starts making the fun amps
    again real soon.  The ones now are sh*t.
    
    Gotta go, digital calls...
    
    Jay
    

    Man, don't talk bad about Kustom when I'm around.  I have a lot of 
    fond memories with my black padded Kustom 200 with 2 15" speakers and a
    15" horn.
    
    Chris D. who_sold_it_to_a_fellow_noter_and_still_misses_it!!!
    

    My father-in-law has one of those rare gold sparkle Kustoms
    with (2) 15 inchers and a horn.  Sounds horrid.
    
    (The horror, the horror...)
    
    ;)

    Must be his guitar!!  :^)
    
    Chris D.

>    The rarest is the blue, with a 3-15 cabinet. 
    
    The guy I bought my first Strat from back in '84 had one of these that
    he was selling at the same time.  It was definately blue sparkle, and
    although I'm sure I couldn't have identified a 3-15 cab at that time, I
    do know it was GIANT!  Stood about 4 feet tall (seemed like) and was in
    the matching blue sparkle gunk.  
    
    I'm glad that I bought the Strat even though it sounded terrible
    through that amp, 'cause it's sounded killer through virtually
    everything else I've run it through (had EMGs in it when I got it).
    
    Greg

    Chris D.
    
    	I think I was that fellow noter who bought that amp from you !
    There can't be that many noters who sold thos things.  I kept that amp
    for almost a year....
    
    		Fender Bullet---> Boss Heavy Metal-----> Kustom
    
    
    
    	Didn't really matter how it sounded.....no one could hear when I
    was done playing. Had to get rid of it ...way to big to move anywhere.
    Those speakers SCREAMED though.  I still wish I had that cab.
    
    Remember the Big Purple Eye ..... we use to call it THE CYCLOPS ;^)
      
    
    Brian....who_also_has_fond_memories_of_the_BLACK_PADDED_monster !!	

    Ok, ok...I'll fess up.
    
    There was a time, when I played a Marshall head through two padded
    Kustom cabs...
    
    Ya see, I sent all my money on the head, so I had to cheese out and buy
    the Kustoms!!  Both kabs had 2 x 15 in them...one was metalflake green,
    the other, metalflake purple!!  (talk about one butt-ugly stack!)
    Eventually, I sold em and bought REAL Marshall cabs.

    Gad!  Never thought I'd find sooooooo many Kustom lovers.  I can'tknock
    them, as they were quite nice as far as guts go, and used some nice
    circuits toobtain that "sound & look".
    
    I've decided about the contest.  Prize: 1 200 watt Kustom (black) head
    complete with the famous cigarette burn on top all Kustoms seemed
    to have. ALL the candy, reverb, dist, etc.
    
    To get it?  Starting monday, I'll begin with the 1st few of 25
    questions.  Answers MUST be posted here.  Coin flips will decide the
    winner in case of ties.  MY judgement is *FINAL*.  Only cost to you
    will be shipping to ya door.  IF ya UPS dude will touch it....
    
    
    Watch for it....if ya guts can take the strain...
    
    Jay
    

    I think it would be best to post all 25 ????? together, and the 1st
    person to answer all correct wins.
    
    Watch for it..coming monday...
    
    Jay
    

>>CSG001::KALINOWSKI                                   18 lines   4-DEC-1990 15:25
    
>>    	I think I was that fellow noter who bought that amp from you !
    
     Yeah, it was you.  I had forgotten the name.
    
>>    Those speakers SCREAMED though. 
    
    Did they ever!  My doctor says I suffered audio trauma when I was
    younger.  I wonder why??  :^)
    

>>    Remember the Big Purple Eye ..... we use to call it THE CYCLOPS ;^)
    
    I remember that.  The amp always reminded be of Gort(sp), the robot
    from the movie The Day The Earth Stood Still.
    
    
    re:? If it stood 4', it wasn't the cab with teh 3 15" speakers.
    
    Chris D.      
    
    p.s. WHo has the amp now, another DECie?

    Anyone have any idea how much it would cost to have a Master volume
    control put on an old Marshall head that didn't originally have one?
    
    Thanks,
    Greg

    RE: Marshall MV mod
    
    It's not expensive, but the BEST MV mod is the one in the back of
    A. Pitman's The Tube Amp Book!
    
    check it out

    What do you consider "not expensive"?  Twenty?  Fifty?  One-hundred
    dollars?
    
    Greg (plotting)

    >Greg (plotting)

    <insert Astro tone(tm)>
    
    Rut-roh...
    
    Umm, seems to me that this mod could be done by you for under $20,
    a tech for under $50.  Am I close here guys ?
    
    jc
    

    
    
    	I got the amp book Buck's talking about if you need copies..
    

    A good tech should charge about $30.  The MV in the GT book IS the best
    if you want to keep the 'real' Marshall sound.  Mouser HD dual pots for
    about $7.  It fits a hole from one of the  4 input jacks.  DO NOT
    DRILL INTO THE AMP!  You'll regret it someday.
    
    I was in Daddy's in Shrewsbury yesterday, and bought a 1-12 sears
    tube amp, made by Danelectro.  $49. They had Ampeg V-4's for $99,
    a black Bassman head for $120.  A MONSTER Traynor head for $125.
    All tube.  The bargins are out there.  I wish I had more $$$$
    The Want Ad had a MINT Lab l5 for $199.  Everybody is selling,
    I guess they need money....
    
    See ya all monday....
    
    Jay
    

    Jay's got it, use one of the input jacks...*I* suggest the low gain
    input on the "bass" (normal) channel, so you can still strap the two
    channels together!

    Well, this is it, and after talking to a few of ya, I think we can
    handle it like this:
    
    There will be 5+ questions per day, for 5 days.  YOU have to answer
    25 of them.  1st to do so, wins.  Simple?  Hope so...
    
    We all know the prize, and there is no cost to enter.  I cannot be
    bribed, or bought, so please try anyway.  I will not ask ????s that
    "..only someone with a reprint of a age-old catalog would know." nor
    will they be simple.  YOU decide.
    
    In case of a tie, the sooner posted of 25 ???s wins, so good luck. I
    will offer hints if they are posted here, thus for everyone.
      
    
    1: Name the 3 brands that Orange (there's one) were sold under.
    
    2: Where did Randall Smith work while designing Boogie amps?
    
    3: What Electronics firm sold Univox amps, guitars, & effects thru?
    
    4: Hyland Amps......US or UK ????
    
    5: What is the TOTAL Max heater current of 4 6550s ?
    
    6: I.S.A.C.  40 Smith st, Farmington NY, 11735.  What amp was/is
       made there?
    
    7: Were the FOXX versions/copies of the VOX amp made in the US or UK?
       HINT: The pics in the catalog tell the truth.
    
    More Tuesday night...  Good luck...
    
    Jay
    

    Well, I think I'll drop myself right out of the running on this one.  I
    know ZERO answers to these questions.  :^)
    
    Chris D. 
    
    Good luck guys.

    re: -1
    
    
    
    
    		.... ditto ...    8^)
    
    non_tech Scary ...

    AW, COME ON..IT GETS BETTER...
    
    8:  What is a Fender Super Showman amp?
    
    9: Some old Vox guitars had what was almost a Super Beatle Pre-amp
       built in.  Tuners, Dist., repeat Percussion, wah-wah, etc.  All the
       candy.  Name 3 models.
    
    a: Who came 1st, white or tan/brown Fenders?
    
    b: We know abot the KT-90, 88, 77, + 66, but was there ever a KT-55?
    
    c: 1985,2720,2048,1959,1967,1958,Capri,2525. Name one of these that is
       NOT (or was not) a Marshall Model.
    
    d: Name 2 other speaker brands ever used by Marshall, other then
       Celestion?
    
    IF these ??? get too hard, I'll keep it going and they will get a
    little more easy.
    
    Jay
    

    well, if it's any indication to ya, I think I've got about half of
    them so far.  The rest ????
    
    I assume the deal is to post answers when you think you have 25
    right, no?

    If ya think ya got over a few, mail me, and I'll tell ya if ya crazy
    or not....answer wise.
    
    Here is today's batch:
    
    z: What amp company used "TONE-X" as a control name?
    
    y: What UK company made a 24-12" cabinet?
    
    x: Who built the "Model-T" amp?
    
    w: CBS owned Fender.  Magnavox designed Ampeg, Thomas Organ butchered
       Vox, Sony slept with Rickenbacker.  Who did RCA mate with?
    
    v: Who built the "O.M.E.C." amp?
    
    u: Kaman music handles Ovation, Trace-Elliot, & Blade guitars.  What 
       other BIG guitar brand can be added to this list?
    
    Good luck...
    
    Jay
    

    Just a few more tonight, I'm tired...
    
    L: Stramp amps were made in what country?
    
    M: Twice every year, NAMN holds a convention.  What does NAMN stand
       for?
    
    N: Was there evber a "PRO" range of Teisco Del Rey amps?  I mean
       100+ watts, stacks etc.
    
    O: Crate makes Ampeg.  Marshall made Park.  Plush was Earth.  Lab is
       Moog.  Who does Dean Markley amps "compute" with?
    
    Jay.
       
     

    Now, about some interesting news:
    
    1:  A store in the UK uncovered 1,000s of OLD fuzz faces and is selling
        them for $80 each.  SOHO Soundhouse in Soho seems to have a gold
        mine here.  I understand they found them in the celler.  
    
    2:  BEWARE!!! In NYC, alot of people have been ripped off with folks
        selling FAKE Marshall rack mount equipment.  The RM stuff can 
        be copied easy, and sold thru ads.  Watch for faint gold paint,
        and for non-UK hardware, like knobs, jacks, etc.  Masrshall had
        "no comment" when I called Korg, but the factory is quite P.O.'d
        over it.  Watch for changes in packaging soon.
    
    On the other front, a few folks are getting close on the contest, I
    hope it ends soon.  I was just trying to get rid of some old gear, &
    thought someone would like the Kustom.  Some have thought I was getting
    "cute" with this.  Sorry you're offended.  It was not intended to upset
    anyone.   
    
    Jay
    

    Re: -2
    
    Should that be NAMM, instead of NAMN?
    
    Mike

    NAMN = National Association of Music Noters?

    of course it's NAMM.   I never was a good typist anyway...
    
    
    Jay
    

    Here's a few more.   A bit harder.
    
    l:  Name 2 amps built in Italy?  Then or now.
    
    2:  What Band instrument company was Vox's "2nd" US agent.
    
    3:  Who owns Schecter guitars?  What amp connection do they NOW have?
    
    4:  RE 4: What 2 amp companies did the heads of Schecter come from?
    
    5:  What color was the grill cloth of a Simms-Watts amp cabinet?
    
    6:  Vox, Orange, and Sola made amps/cabinets on stands, did Marshall
        ever offer stands for their units?
    
    It's getting close, and only a few more ??? remain.  After the contest,
    it will be business as usual.  Hope you're all here.
    
    Jay
    

    A few more ???s:
    
    k: Burns guitars also made amps.  Name 2 models.
    
    l: MOSFET, HEXFET, CMOS, VMOS, DMOS, SMOS, QFET.  Which design does not
       exist?
    
    m: Where were "Trucker" amps built?
    
    n: Adam Hall ltd sells what products?
    
    o: Who makes Marshall output transformers?
    
    p: What fact does Ovation, Rickenbacker, Gibson & Vox have in common?
    
    q: Before they were bought by Japan, who last inported Hiwatt to the
       USA?
    
    
    I am looking forward to attending the NAMM show this Jan, and will
    report any/all poop!  You folks in Calif., bribe some store to help
    ya to go, as you have to be in the BIZ to attend.  Need help? let
    me know. 
    
    Jay
    

    A few more tidbits:
    
    k: Name 4 WEST amp models.
    
    l: What brand guitar, tape & all, did  M. Farner of GFR use with his
       West amps?
    
    m: Name 4 CORAL amp models.
    
    n: Did Marshall ever have another dist. house in the US besides Korg/
       Unicord?
    
    Hope someone is getting closere & closer, I'd like to get this out
    by Xmas.  Should be any day now.
    
    Jay
    

    Last batch before the XMAS holiday:
    
    s: What brand of strings, sold by a amp company, did Eric Clapton
       endorse?
    
    t: BOSE 901 speakers were a DIRECT take off of what amp companies'
       PA speaker?
    
    u: Name the HI-tech pa speaker company owned by Pioneer?
    
    Take care, have a happy holiday!!!
    
    Jay
    

    Well, I'll have a go.  Some of these are real swags, but I think
    I've got enough right to at least get close to the magical 25.
    
    Oh yeah Jay, the bottle of Scotch is in the mail :-)
    
    
    1: Name the 3 brands that Orange (there's one) were sold under.
	Orange, Matamp, Musonic
    
    2: Where did Randall Smith work while designing Boogie amps?
	Prune Music
    
    3: What Electronics firm sold Univox amps, guitars, & effects thru?
	Allied
    
    4: Hyland Amps......US or UK ????
	US
    
    7: Were the FOXX versions/copies of the VOX amp made in the US or UK?
       HINT: The pics in the catalog tell the truth.
	UK
    
    8:  What is a Fender Super Showman amp?
	Solid state, 140w RMS
    
    9: Some old Vox guitars had what was almost a Super Beatle Pre-amp
       built in.  Tuners, Dist., repeat Percussion, wah-wah, etc.  All the
       candy.  Name 3 models.
	Cheetah, Ultrasonic, Grand Prix
    
    a: Who came 1st, white or tan/brown Fenders?
	White
    
    b: We know abot the KT-90, 88, 77, + 66, but was there ever a KT-55?
	No
    
    c: Name one of these that is
       NOT (or was not) a Marshall Model.
	2525
    
    d: Name 2 other speaker brands ever used by Marshall, other then
       Celestion?
	McKenzie, Goodman
    
    z: What amp company used "TONE-X" as a control name?
	Vox
    
    y: What UK company made a 24-12" cabinet?
	Wem
    
    x: Who built the "Model-T" amp?
	Sunn
    
    v: Who built the "O.M.E.C." amp?
	Orange
    
    u: Kaman music handles Ovation, Trace-Elliot, & Blade guitars.  What 
       other BIG guitar brand can be added to this list?
	Hamer
    
    L: Stramp amps were made in what country?
	West Germany
    
    M: Twice every year, NAMN holds a convention.  What does NAMN stand
       for?
	National Association of Musician Merchants
    
    N: Was there evber a "PRO" range of Teisco Del Rey amps?  I mean
       100+ watts, stacks etc.
	No
    
    O: Crate makes Ampeg.  Marshall made Park.  Plush was Earth.  Lab is
       Moog.  Who does Dean Markley amps "compute" with?
	Spectra
    
    2:  What Band instrument company was Vox's "2nd" US agent.
	Primo Music
    
    3:  Who owns Schecter guitars?  What amp connection do they NOW have?
	Aspen & Associates; they make GT Electronics amps.

    4:  RE 4: What 2 amp companies did the heads of Schecter come from?
	Acoustic, SWR
    
    5:  What color was the grill cloth of a Simms-Watts amp cabinet?
	Purple
    
    6:  Vox, Orange, and Sola made amps/cabinets on stands, did Marshall
        ever offer stands for their units?
	Yes
    
    k: Burns guitars also made amps.  Name 2 models.
	Exterminator, Professional
    
    l: MOSFET, HEXFET, CMOS, VMOS, DMOS, SMOS, QFET.  Which design does not
       exist?
	SMOS
    
    k: Name 4 WEST amp models.
	Fillmore, Winterland :-), Avalon :-) :-), Altamont :-) :-) :-)
    
    l: What brand guitar, tape & all, did  M. Farner of GFR use with his
       West amps?
	Messenger
    
    m: Name 4 CORAL amp models.
	Kilowatt, Californian, Texan, Danelectro DX-250
    
    n: Did Marshall ever have another dist. house in the US besides Korg/
       Unicord?
	Yes, Merson Musical Products was one
    
    u: Name the HI-tech pa speaker company owned by Pioneer?
	Altec-Lansing
    
    
    Merry Christmas, Jay, and to all the other tube heads out there
    
    /rick

    Kaman also owns Takamine !!
    
    Mark

    WELL!  Rick, you got it.!!!!!  I'll post all answers tommorrow, but
    e-mail me for shipping details.
    
    Grats' are in order for all the folks who entered.
    
    Jay
    

    Just a quick note of happy new year to all who note here.  DON"T drink
    & drive, and behave yerselfs...
    
    By the way, I just found a old Ampeg stockholders report for 1965! 
    Full of neat-o info, and hidden meanings....Free to anyone who wants
    a copy, it's worth a SASE to:
    
    Jay Tashjian
    P.O. Box 189
    Worcester, Ma.  01602
    
    I'll throw in a few other rare items from Ampeg's history too.  
    
    I promise the answers to the quiz ??? when I get back, I haven't had
    the time this week.   Best to everyone....
    
    Jay
    

    Just thought I'd let everyone know, I picked up my prize earlier this
    week.  It's as advertised, a Kustom 200 padded head with all the
    trimmings.  One channel has reverb and tremelo; I got some bitchin
    surf tones here.  The other side has the "harmonic clipper"; still
    experimenting with this one.  Let's just say, I haven't put my Marshall
    up for sale quite yet.
    
    The head is in exceptionally clean condition, and really built solid.
    The tuck and roll is a thing of beauty to behold, if you're into that
    sort of thing.  They just don't make stuff like this anymore.  As an
    added bonus, it doubles as a great piece of living room furniture!
    Try that with a Kitty Hawk :-)
    
    /rick

    Here's a few answers to the ????s...
    
    Name 3 brands Orange was made under:  Orange, Mattamp, White.
    
    Randall Smith worked a Prune Music.
    
    Lafayette sold Univox under both names.
    
    4 6550's (heater current)= 6.4 amps
    
    Hyland amps?:: USA
    
    I.S.A.C. was Plush/Earth's address.
    
    Foxx was UK units.
    
    More Later.
    
    Jay
    

    White Fenders came 1st.
    
    There was never a KT55
    
    #2525 wasn't a Marshall Model
    
    Mckenzie, Goodman, & JBL filled MarshallCabs from the factory.
    
    Vox used "TONE-X"
    
    WEM & Orange made 24-12" cabinets
    
    Sunn built teh Model-T.
    
    Hamer is handled by Kaman too...
    
    Stramp was made in W. Germany
    
    Teisco Del Rey made stacks, The "Checkmate 50 & 100 (s)
    
    Dean Markley computes with Spectra
    
    King instruments blew the horn for VOX
    
    NAMM:=== National Assoc. of Musicial Merchants.
    
    More tommorrow...
    
    

    
    	Hey Jay, I got one for ya - who made the "Exterminator" amp
    	in the late '60's? I believe it was the biggest single cab
    	amp ever made.
    
    	Neal
    
    
    

	Picked up a ~67 Bassman head cheap. Two things I want to do:

	1. Install a proper 3-wire power cable.

	2. Eliminate the quiet "sizzle" sound in the amp. I suspect
	   this will entail replacing the filter caps in the power
	   suppy. Am I correct?


	Any pointers on doing these? Anybody able to send schematics to
	ZKO3-3/X18?

	ccb

    According to Rick Calcagni, bassist extraordinaire and recent dad, one
    can merely take a three line cord, run the white and black to the 
    the two leads previously occupied by the two-conductor cord, and attach
    the ground leg (green lead) to the chassis.  I did it on my Deluxe with 
    no ill effects.
    
    Can't help with the 'sizzle' problem.  
    
    Regards,
    John
    

re: .197

I'm not sure what you mean by sizzle but crackling and popping sounds
are notoriously caused by bad 100K resistors on the 9 pin miniature
plates. These are the preamp and driver tubes: 12AX7 and 12AT7 types.

Leaky filter caps create a 60Hz hum, which can be quite loud depending upon
the level of degradation of the cap. They often need to be replaced. In fact,
I have two old Fenders that I need to do right now. Finding caps with a
sufficiently high working voltage (525V for your amp) is difficult these
days. Mouser Electronics has high voltage capsup to 450 volts. Maybe someone
can recommend another source.

As for a grounded power cord, just make sure yu don't get one too bug
for the hole in the chassis. Solder an eyelet onto the ground conductor
and bolt it down to the chassis using one of the existing mounting screws,
like on the power xformer. Use an eyelet with teeth.

I might have a schematic. Post or send me the number printed on the 
tube chart inside the head. It should be something like "AB765".

--rjb

    
    	I just repaired a '70's Twin Reverb with the same problem
    	and replacing all the .5w 100k ohm resistors did the trick.
    	
    	Thanks again -rjb- for the Groove Tube book; the bible of
    	guitar amp stuff.
    
    	Neal
    

	I recently changed most of the tube sockets in my twin reverb
	(as well as some of the resistors on them) and the personality
	change quite nice. The 12AX7 sockets were in the worst shape (one
	can only wonder what happened to them - someone tried to clean
	them once & they were made worse), and I had one 6L6GC socket that
	would have tubes get very noisy in (bad contacts).

	I got the sockets cheap (since no-one orders them anymore) at 35
	cents each (yes, I bought a lot of them - they can sit at my house
	just as well as a shop - I never know when I might need one).

	It took about 2 hours & I changed the sockets one at a time. If
	you do this, take your time & use a low wattage soldering iron
	(30 watts or so) to carefully remove the wires & not damage the
	insolation.

								Jens

    I have an off-brand (Alamo) tube amp that makes several loud popping 
    noises right after power up.  After running for about a minute, it is
    fine.  Any ideas?  I don't have schematics, but the amp design appears
    similar to a silver-face Fender champ (6V6 and a 5Y-something).
    
    Jim

Re: .-1

Sounds like somewhere in there is a component that is defective and 
is sensitive to heat. The temperature change that occurs within the component
shortly after power-up causes enough expansion to "cure" the fault. The 
culprit may be found by lighly tapping the components with a *PLASTIC* tool
while powered on. Could also be a cold solder joint.

--rjb

	The number on the tube label is A-165

	Daddy's is blowing out tubes with the Mesa-Boogie label on
	them for 1/2 price. I snarfed 3 12AX7A's for $4 each and a
	duet of 6L6-GCs for $18. These are decent prices.

    Some more answers...
    
    A Super shoman is a 150 watt, solid state stack with fuzz, tuner and
    powered cabinets.
    
    Delta, grandprix, Invader, Hawk were Vox Active guitars.
    
    SMOS does not exist.
    
    Trucker was built in the UK.
    
    Adam Hall makes Cabinet/amp hardware.
    
    Drake ltd. makes transformers for Marshall.
    
    Ovation, Rickenbacker, Gibson & VOX, along with Marshall were/are
    dist. by Rose Morris ltd. 
    
    Guild inported Hiwatt last.
    
    Teisco Del ray made stacks, the Checkmate 50 & 100.
    
    Orange built the O.M.E.C.
    
    The Exterminator & professional were Burns amps.
    
    West made the Fillmore, Avalon, Granade, and the Bass 100.
    
    GFR's guitar player used a rare Messenger guitar.
    
    Gotta go back to work, more later.
    
    Jay.
    

    
    Can anyone tell me anything about:
    
    GMT amplifiers
    
    and
    
    Bruce amplifiers?
    
    
    These items are circa 1974.
    
    Thanks,
    
    Brian

    I'll have to check up on bruce, but GMT was what is now GK.  I have
    any/all schematics for the GMT line.  These units were before GK went
    ultra-smallin stuffing as much as possiable into as small as possiable
    space.  Traynor copied the look in the "MONO-BLOCK" series.  As I 
    mentioned before, inside the Zappa "Roxy & elsewhere" LP, there is
    pictured the GMT I sold him.  The 600 & 300 units were the same,
    except for output power stages.  IF you find any GMT around, they
    are *SOLID* built, and worth the cheap $$$ asked today.  IF you
    have need of any special info, e-mail me & I'll arrange to send ya
    some copies of lit & schematics.
    
    Off to the job...
    
    Jay
    

    
    Jay, do you still have the M1?  How is it working out?
    
    	-pat

    re: 208  Bruce, GMT amplifiers
    
    Thanks, Jay, for the info on these amplifiers.  I don't own them
    but was reading about them in an old issue of GUITAR PLAYER.
    
    Brian

    Just a quick note....tonight I bought a Black-faced Fender
    Deluxe-Reverb amp in near-mint cond., for all of $40!!!   Needs
    tubes, but that I got.  Bad news is I got it from a old ex-musician with
    a nasal problem, if ya understand.  But, that's all he wanted for it.
    
    SEE...the deals are still out there.  Check the for sale area, as the
    amp is for sale/trade.   Offers?   I want (bad) a good Danelectro
    shorthorn guitar.  Help?
    
    After next week, when I return from NAMM, things will pick up.
    
    I promise....
    
    Jay
    

    I too, have landed some great deals from musicians with a lust for nose
    candy.  It's a shame, but if I didn't buy it someone else would.
    
    Scary

    Hey Jay T.
    
    Cool dead dude!  If you run across any old M-word (Marshall) amps,
    pick em up for moi, ok?  I'll pay ya...
    
    Buck, who NEVER gets deals  ;^9

    
    
    
    
    
    	dang, Jay.. makes my silver face for 199 that needed tubes look
    like a screwin'.... Feel bad for addicted musicians... ;^(

    Jay,
    
    In case you didn't know, Mr. C's in Marlboro has had a black shorthorn
    (single PU) on the wall for awhile.  They just got in a nearly
    immaculate copper shorthorn bass marred by a crack in the back...aargh,
    it makes me sick to think about it.
    
    Unfortunately, they know what these things can be worth and price 'em
    accordingly.  
    
    Have a doubleneck already?  I always wanted one of those...
    
    						Brian

    
    
    
    	Dr. Jay, I just got my deluxe reverb back from my local tube whiz
    kid and I'm delirious with the tone.. however I notice that when I
    switch to vibrato (for some wicked hip Ventures chords, he) the volume
    is much less than when not switched to vibrato AND there is a distinct
    static click that corresponds to the sweep of the vibrato, what I mean
    is, it follows the vibrato speed and sounds like I was tuning real fast
    past a shortwave station on an old short wave receiver... kind of a
    staticy click (I know I don't get creative writer of the year for
    this...) I'm going to call back my tech on Monday, but I'd like to hear
    your opinion and the opinions of my fellow guitar noters too... How
    about mighty valve-guru?  Whatdaya think
    
    I got tow-own, I got tow-own!!!
    Gree Vee King  [;^)))))))

    It seems like yerVIbrato tube is bad. 12AT7's, when they go, go big
    time, although they are one of the strongest tubes around.  Try to
    replace that, check the 25uf/25vts caps connected to both sections
    of that tube.  IF you got a F/S attached, check it out too.
    
    I too fell bad about addicted musicians, but I get many a deal that
    way, like a Gibson Firebird V, custom colour, for $85!, a few UK
    amps all under $50, and my pride, which I still own, Tweed Twin
    in MINT shape for $100! I will not support habits, but do understand
    that if not by me, they'd go to others.  I notice anything sold within
    50-200 $$ seems to be for nose poison.  Sad.   Just goes to show, dope
    is for dopes....
    
    Mr C has had some good Dan's for sale, I bought a single cut/single PU
    axe with 'D' on the pickguard with a Viscount model Dan amp for $150.
    Jim is an al'right dude, and has always treated me more then fair.
    
    I leave for NAMN this Thursday.  Can't wait.  I'll report all in the 
    Guitar Notes....
    
    Jay
    

First of all, Jay, let me reaffirm your own feelings. Buying something
from a junky is not wrong. Don't apologize. You didn't give them the 
habit. You're just the luck SOB that was standing there with the cash 
when they needed to liquidate some inventory. You got some scores. In fact,
they're so good, maybe they are criminal! Just kidding.

Secondly, regarding Fender vibrato circuits: I find that they don't
age very gracefully. My two black fenders have extremely weak if any
vibrato effect. I've never tried to troubleshoot them, but I have changed
the 12AT7. What else typically degrades in this circuit? The photo-
sensitive resistor? The lamp that drives it? I'd like to get it going
again. It's a classic effect.

--ron burati

    While we're on the subject of little Fenders, my silver face Princeton
    Reverb started acting strangely after a re-tube about a month ago.  
    Ten seconds after I light it up, it starts feeding back (nearly perfect
    C#) at low volume, for about five seconds.  The feedback comes on
    gradually and disappears in the same way.  The volume pot has no effect,
    but the reverb level does: if I roll off the reverb during the midst of
    the transient feedback, it goes away.  It does not require a rocket
    scientist to point a finger at the reverb circuit, but since there are
    no adjustments inside this amp (at least I didn't see any when I opened
    it up), I'm at a loss to figure out what's causing the feedback.
    
    Since it's so transient and doesn't affect the sound, IMO, should I just
    leave it alone?
    
    The tubes were order from Mesa, a long time ago, and never used until
    I installed them.
    
    Regards,
    John

    1st off,the resistor/photo element in old Fenders is a GOOD guess of
    the problem.  I ALWAYS replace them, and MDS in Chicago has them cheap
    too.  
    
    As far as the reverb problem, the reverb transformer can go, any
    resistor feeding B+to the circuit will cause the feedback, but I 
    would check connections to the springs, and/or the spring mini
    transformers (housed inside the can) may be bad.  Best in that case
    is to replace the unit.  Reverbs can be tricky but 50% of the problems
    check back to a bad tube or can.  Use 12AT7s for reverb & tremolo.
    
    I pushed my trip to Sat., and hope this NAMM show is better then the
    last.  By the way, I caught "Slipknot" a few days ago, and everyone
    should go see these guys.  Haven't had that much fun with pants on
    in a l-o-n-g time.
    
    
    Jay
    

    Well, I'm back from NAMM.  What a waste of time.  The current musicial
    instrument scene really stinks.  Amp wise?, well Marshall has new
    models all including the (tube -l.e.d.) monitoring system.  What a
    stupid idea.  Remember, the more "toys" like this, the worse the amp
    should sound...and last.
    
    Fender showed Vib-Verbs, Twins, and Showman vintage amps, all with
    much higher $$$ tags then the Bassman re-issue.  Nowhere were the 
    Gibson & Gretsch re-issues.  Also not there was Orange. 
    
    Boogie showed the normal stuff.  Nowhere on the floor was the new
    Yamaha units, but they were shown "a la private showing" which is now
    becoming a "in thing".  They look nice, but not too well made.
    
    EVERYTHING is going UPPPPPPPPPPPPPPPPPP in price.
    
    Yep, I wasted $1k to go there.  I hope someone sold something, as there
    were not too many dealers there buying.  Heck, between the entry fee,
    Hotels & airfare, who had $$$?
    
    Later.  I'll go thru my new stuff, and report more later.
    
    Jay
    

    Just a quick note again about a few things at NAMM:
    
    Yes, Kramer filed chapter 11.  After Eddie left, so didn't the business
    and Kramer is owed $$$$$$$$$$$$$$$$$$$$$$$$$$ from it's dealers, and
    hench owe $$$$$$$$$$$$$ to everyone else.  Watch for them to reform
    and be bought out by someone else.  Gibson is in the running.
    
    Marshall's tube/solid state units may NOT fly.  Major problems
    stopped them from releasing these units 2 years ago.  Besides, they
    do sound very bad.
    
    Anyone else have ???? like these, just e-mail me.
    
    Be back on Monday.   And be back to as normal as I can get.
    
    
    Jay
    

    Just a few seconds from work.  I've gotten alot of mail about tube
    prices, so I went around Mass to check it out.  Damn, I can't belive
    what folks charge.  Daddy's has 2-6L6GC tubes for $35!  2-6550's for
    $50!  The others are no better.  Pure rip-off....
    
    Here is a address or two for tubes, far less then the music stores
    charge.
    
    New Sensor Corp.   1-800-633-5477  or  1-212-980-6748
    245 East 63rd street Suite 526  NYC, NY.  10021
    
    (run by old friend, Mike Mattews of Electro Harmonix fame, prices
     are cheap.  6L6GC @ $4.50,  6550's @ $12.50  That GREAT USSR tube,
     the 6L6WGC/5881 Military spec, is ONLY $6.85 ea.  The *BEST* 6L6
     ANYWHERE!  They have a $40 min order)
    
    Triode Electronics       1-312-871-7459
    Box 578571  Chicago, Ill.  60657
    
     (EVERYTHING for tube freaks.  Cheap tubes, transformers, tools,
      chassis, sockets, caps, EVERYTHING!  Besides, they are great
      folks to buy from, and learn from.  The ONLY source for out of
      print tube manuals. GET THIS CATALOG!!!!!!!!)
    
    So there, no more excuses.  By the way, the newest Glass Audio
    magazine has a GREAT article/schematic of the Carver Silver 7
    mono block tube amp, using * 15 * KT88 or KT90 tubes a channel, &
    as shown on the cover of Audio magazine.  FOR $10 A YEAR, YA BETTER
    SUBSCRIBE TO THIS MAGAZINE!  Besides, every issue has the Triode &
    New Sensor price sheets & tube lists.  Oh ya, save another $30 for
    the 3-years of back issues. Published twice a year, soon 4 times a 
    year.  A Must.
    
    Talk to ya later.
    
    Jay
    

|    as shown on the cover of Audio magazine.  FOR $10 A YEAR, YA BETTER
|    SUBSCRIBE TO THIS MAGAZINE!  Besides, every issue has the Triode &
|    New Sensor price sheets & tube lists.  Oh ya, save another $30 for
|    the 3-years of back issues. Published twice a year, soon 4 times a 
|    year.  A Must.
        
        So how  does  one  go about subscribing to this ?  I've never
        heard of Glass Audio magazine and would be real interested if
        someone could post a  number/address.   Please ?!?!?!?  (Beg,
        grovel, whimper whimper. :^))
        
        Matt

    The address for Glass Audio , TAA, Speaker Builder etc is:
    
    TAA
    box 176
    Peterborough, NH.  03458
    
    I loved the 1st issue soooo much, I drove to NH to buy the rest.
    
    ALSO, check the new books on tubes:
    
    Sage of Vacuum tubes
        &
    70 years of tubes & Valves.
    
    Both for $35!
    
    I suggest ya get them.  NO ONE offers more info on tubes then this
    source.
    
    Jay
    

        Thanks Jay !
        
        Matt

    The Speaker Builder, The Audio Amateur, Glass Audio come from the same
    place.
                                                                 
    The telephone number is 604-924-9464, and they take Master Card
    and Visa.  And ask for there kit catalog, which has some tubes,
    resistors, opamps and capacitors in it as well. 
    
    					roy

    	I believe the area code for NH is 603....
    

    
    
    	Jay, my amp tech used russion tubes on my deleuxe.. beefy looking
    little buggers and so far I'm real pleased... the brand name is "Ruby"
    I think!

    Those tubes are something else.  In Boogies they sound louder then
    ever.  The 'RUBY' name is a attached brand.  The factory name is
    Sovtek I belive.  Great tubes, the best 6L6GC ever made.
    
    Since I've just re-tweeked my old Deluxe, I'll offer a few real
    cheap mods for ANY tube Fender amp to get more out of it, but
    retain the same sweet sound.  Very minor stuff, but worthwhile,
    and needing no holes drilled, etc.  I'll enter this on Monday.
    
    By the way, the 12AX7s from China are really a 7025 replacement, tone
    wise, so if you want to replace the preamp tubes in a Marshall or
    any UK style amp, use Mullard 12AX7s to retain the sound.  The
    China tubes will sound too "Fender-ish"
    
    Jay
    

    I could use some suggestions. I have a Mesa Boogie Mark II B (as
    near as I can tell...the rear panel was gone when I bought it) and
    I use it to drive a Mitchell Sand cab loaded with a couple of JBL's.
    This rig makes the "sweet" sounds that I have been seeking for years
    but those "sweet" sounds occur at paint-peeling volume.
    Options?
    
    Thanx, 
      Scotty

    One nice addition to any Fender amp is to replace ALL 100k B+
    resistors in the preamp with 2% Flameproof 1-watt units.  Quiets
    things up REAL fast.  Next, replace the input 68K & 1M resistors
    with the same units.  Now, replace the input wires to the tube
    grids with shielded cable (Mike cable is good), grounding one
    side of the shield.
    
    And, replace the B+ filter caps with the below units.  If the B+
    reducing resistors are 10K each, replace them with 8.2K 2-watt
    flameproof units.  These are the ones in the cover with the B+
    caps.  IF they are any other value, keep them at the same valus &
    replace them with 2-wt FP units.
    
    The caps are from Mouser, #19AF047, Rubcon 47uf/450wvdc units that fit
    inside the cover perfectly.  They cost about $4.50 each.  This will
    increase the b+ cap supply over 300%  Adds about 10 watts rms too.
    
    More later.
    
    Jay
    

    Speaking of shielded cable, I see that the wire inside one of my
    guitars is shielded, or in a metallic sheath. I cannot seem to buy 
    this kind of wire anywhere. Where can I get some for some rewiring 
    work I want to do? Do I really need it?
    
    Dave Kinney

    Which note out of the 233 replies in this topic talks about Jay T's
    preamp tube technices re: painting, wrapping in tape, etc?!?
    
    Thanks in adavnce,
    Buck, who can't find it

    Buck,
    
    SEARCH/NOTE=1994.* PAINT 
    
    yielded reply .71
    
    Mike

    
    	Re .233
    
    	I find that by "gutting" a defunct Cassette tape machine, will
    yield enough of the shielded wire you need to do the inputs mods
    to several guitar amps. These can be car stereo types, portable
    mono dictating machines and of course the home HiFi ones.
    
    	Joe

    Any Radio Shack should have rolls of it.  The reason is, that ANY noise
    or unwanted his/hum starts with the 1st tube stage.  To do it right,
    one could even shield the input resistors (attached to the input jacks
    on Fenders, Marshalls, etcs) with foil, 1st taping all exposed
    resistors so they do not short out.  Some amps even shield the jacks
    too.  But, the wire going to the 1st stage has to cross some B+ wires,
    which introduce hum.  
    
    Later, gotta get to work...
    
    Jay
    

    I have set of Boogie 12AX7A's that come stock with this black rubbery
    stuff wrapped around the tube.  Looks like thick shrink wrap.  Is this
    the same kinda thing ??
    
    jc

        You can get Sorbothane tube dampeners and sheets from a lot of
        sources.  Sorbothane can be used to dampen vibrations and
        microphonics in tubes, caps and ICs.
        
        Though I haven't tried it, I suspect that one of the best things
        that can be done is to dampen the PWB by mounting it on washers
        made out of sorbothane or other similar stuff.  It should cut
        down the major vibrations that affect all the components on the
        board.
        
        One place I use is -
        
                K.E. Lang
                6501 Lancret Hill Dr.
                Austin, TX 78745-4713
                (512) 441-3479
        
        Drop him a line asking for a catalog.  Include a $0.29 stamp or
        IPC, if your outside the U.S.  He'll ask how you heard about him,
        so let him know I sent you and that your modifing music equipment.
        
        {I get no discounts or other favors from him.}
        
        He also has some stuff called UDC - Ultimate Dampening Compound.
        It comes in small strips or 25 ft. rolls and is quite sticky.
        I've used it per his recommendations on tonearms.  It really does
        a nice job of breaking up vibrations.  this would be good for
        chassis applications - such as around chassis mounted filter
        capacitors and the like.
        
        Bob

>    (run by old friend, Mike Mattews of Electro Harmonix fame, prices
>     are cheap.  6L6GC @ $4.50,  6550's @ $12.50  That GREAT USSR tube,
>     the 6L6WGC/5881 Military spec, is ONLY $6.85 ea.  The *BEST* 6L6
>     ANYWHERE!  They have a $40 min order)
    
Are they OK for 12AX7/12AT7's too. I can probably get to $40 if i bundle
everything together.

	mark

    Yup, he has the China 12AX7As too.  
    
    K.E. Lang is a good source for such items, and he has written some
    great articles on MOSFET power amps too.
    
    gotta run, more tommorrow..
    
    Jay
    

    Opps...just purged all my current mail.   IF you sent me e-mail in the
    last 5 days, please write again.
    
    Sorry.....
    
    Jay Tashjian
    

How important are matched sets when buying output tubes??

    mark

    -1		VERY!
    
    

    I think matched tubes are important, but I think that high quality
    tubes are matched closely enough.  I think "Groove Tubes" are kind of
    a rip off...  Basically, because they take bad tubes, match 'em up
    with other bad tubes and rate them "soft"...
    
    jc

    Coop's right.
    
    I should have qualified my reply of -2.
    
    What I mean was, you shouldn't have just "any two tubes" in your output
    section.  However, this doesn't mean you should go out and spend
    $50-100+ on a pair or quad of GT or MESA tubes.  They're just tested
    tubes, painted with a logo...nothing really that special IMHO.

    Yeah, I figured I'd be really cool and get those matched extra soft
    GT tubes... Paid out the butt for 'em and they STUNK.  Didn't
    last a damn year.
    
    AudioGlasic is my tube of choice. $6.95ea. for 12AX7's.  Cheap and
    just as good.
    jc

I was thinking of ordering a couple of the USSR 6L6's and was
wondering if i just purchase 2 off-the-shelf how close they would be
and if i could adjust any imbalance in the amp. Or should i order 3 or
4 (only really need 2) and pick the 2 that match the closest?

 mark

    Matched tubes are good, unless you can set the bias seperatly for
    each tube.  I'll enter on monday a simple circuit to do this
    on most any amp.  GT tubes are more then 'bad' tubes rated soft,
    but tube prices to the musician have always been a rip off, and
    Mesa/Boogie & Peavey are no better, nay worse.
    
    Later...
    
    Jay
    

    
      Jay - maybe you can clarify this.
    
      I had heard about the same thing that Coop was saying, that the
    soft GT tubes supposedly "crunched" better but didn't last as long.
    Is the main reason the difference in the gases, specifically the
    amount of air content the the getters didn't get rid of. I'm sure there
    may be other factors, but I think this is the primary one.
    
    							-B()()M-

	I've never tried for matched tubes on any of my amplifiers (Twin
	Reverb - used to own: Bassman, Bandmaster & old Sears Silvertone -
	Circa 1960), and have not had any problems as long as the tubes 
	were good. In fact, One of my spares (I carry enough to fully re-tube
	my Twin) is an Delmonico 6L6GC - this company went away in 1962,
	and it is a very good tube. My 1957 Fender Reverb unit (One of my
	brothers bought it new, that's how I know the vintage so well) has
	never been re-tubed & It got used a lot until I got a Digital reverb
	unit.

	I don't think that matched tubes are worth the money if you are into
	general useage of your Tube amplifier. I've got a Set of SOVTEK's 
	(6L6GC's) in my Twin now. I Had some of the Chinese 6L6GC's in
	there, but the shape of the tube made the one nearest the output
	transformer occasionally vibrate against it. I had a lot of micro-
	phonic tubes turn up, but only in this one socket. Hence I switched
	to the different tube shape.

	The SOVTEK's are more gassy (glow blue) than the Chinese tubes 
	(only the elements glowed in those).

							Jens

    
    	My Philips 6L6GC's are still goin strong which I bought over the 
    	counter when I bought my KH.  They are just garden variety
    	electronics wholesale junk.  They glow blue too.  One of my matched
    	GT EL34's ate it in only a month.  

    GT  and others match tubes in sound to others they have in stock.  I
    find the Sovteks to be the CLOSEST to the old 5881s.  The price
    is good, and they sound great.  ECG/Philips MADE a great tube, lasted
    long, but not the best sounding 6L6 made.
    
    Yup, element size, shape and construction are the biggest factors to
    tube sound, along with glass thickness.  Gas matters too, but only
    if the tube is not 'packed' with the gas completely.
    
    Although I am a GT dealer, I do buy from other sources.  I feel
    that GT tubes are great for traveling musicians, and or tech shops
    that need a "music store type" source for tubes.  Out of all the 
    matched tube music store supply type tube sources (say that 10
    times fast), they beat Boogie hands down.
    
    Jay.
    
    

    A little amp news:
    
    Ampeg has been forced to stick with tubes, as at NAMM dealers 9-1
    stated "if we want Crate, we'll buy Crate".  Good for them.
    
    Vox still has no US Dist.  Angela Inst in MD is the nearest bet.
    
    Gretsch has dropped all amp plans.  No word why, but we'll guess
    $$$$ problems.  I hope not, as they make great guitars.  Still.
    
    New Sensor (the tube/Electro Harmonix folks) have a item called the
    "Soul Kiss" which allows ya to control most any function by moving
    ya lips.  You can't sing at the same time.   Sorry.
    
    Gibson turned down a invite to buy Kramer.  Peavey is still thinking
    about it.
    
    Never a dull moment...
    
    Jay
    

    Had a chance to look into the new Yamaha tube amps, and I must say
    that although the $$$$ is high, the product is good.  Try them out.
    
    Fender will ship tan/tweed Showmans by late July.
    
    There is a new device to replace 1 preamp tube with 2, called a t-bar.
    DON'T USE THEM.  Major problems have arised.
    
    SRD The Rockman people have decided to drop the amp line.  Good, they
    were real bad.  Pure Junk.
    
    Carver will go into the MI amp, mixer board market very soon.
    
    till later..
    
    Jay
    

    Just a few notes about the current price of vintage UK equipment:
    
    Marshall Heads:
    
    Plexi 100 tremolo:              $1k
          100 Super Lead:           $1.5K
         
    Super Lead 100:                 $999
    200 Major   (a steal):          $500
    20 watt heads:                  $400
    Plexi JTM45s:                   $1k & up & up & up
    
    Marshall Cabs:
    
    4-12 angle, 1970                $800+
    4-15 angle, 1979                $500
    8-10 angle, 1973                $400
    
    Vox AC30s:
    
    Tan, 62, mint showroom:         $1.5k & up & up & up & up
    1964, TBR, dead mint:           $1.8k
    other AC30s in dog to VG+:      $500-$1k
    
    Park 100 watt head:             $900+
    Orange 100/120 head:            $500+
    Orange 4-12 cab:                $500
    Hiwatt 100 head (UK)            $500
    
    As you can see, the prices just go up beyond control.
    
    Later.....
    
    Jay
    

    Now ya know I'm a luver of tube units & respect thoses old units but
    the below ad makes me sick from the April 91 GP:
    
    1 JTM45 head one of the 1st 100 made:  $4000.00
    
    This is too far!  I want names & address of any fool who buys this!
    
    I have 2 in boxes I don't know when they were made ## wise but will
    sell a *little* less then $4K!
    
    Sucker born every 45 seconds...
    
    Jay Tashjian
     

    GAD...I can't find the Vintage Fender topic...so here is the solid
    state rectifier mod I promised to that topic.
    
    
    1st remove the rect tube
    
    wire 4 1000vt/2.5+amp diodes like so:
    
    
                         
    pin 8 ------------->|------------- pin 2
    pin 6 ------------->|------------- pin 8
    pin 6 ------------->|------------- pin 4
    pin 4 ------------->|------------- pin 2
    
    This works with GZ34'a and other alike tubes.  Can be reversed
    toot-sweet...
    
    pin 8 is the AC in
    pin 2 is B+ out
    pin 4 is the AC in
    pin 6 is ground
    
    Take it easy and everything will be ok.
    
    Jay Tashjian
    
                       

    Just a quick note of goodbye to everyone on the guitar notes,
    as my stretch at Digital ends VERY soon.   Thanx to everyone, I
    enjoyed talking/meeting etc ya all.  If I can help, write
    me at: 
    
    Jay Tashjian
    P.O. BOX #189
    Worcester, Ma.  01602
    
    Jay Tashjian
    
    .....going Solo...
    

    Good bye and good luck.
    
    Chris D.

    Jay,
    
    Good Luck. I'll be in touch. You can bet on it.
    
    --Ron Burati

    
      Good Luck Jay -
        We'll miss all your support for us Tube-heads!
    
    					-B()()M-

    Thanks Jay,
    
       You've provided alot of people with a better understanding of
    amplifiers. We appreciate your help and sharing of knowledge.
    
    Best Regards!
    
      John

    Anybody got any great ideas on how to clean up an old tube socket?  I'm
    getting some noise blasts due to some grunge in the socket.  Cleaning
    the pins on the tube and spraying some contact cleaner into the socket
    controls it for a few weeks, but I'd like to get in and clean the
    socket out somehow.  Pipe cleaners and swabs are too wide.  Last resort
    is to swap in a new socket.
    
    							Brian

    Short of replacing the socket, which sounds in order here, you might try
    tightening the inserts. These get sread-out over time.  It's a little
    tricky. You need a very pointy instrument (not an Ibanez :] ). Pry the
    inserts from their outside to make the opening smaller.


    push here---->/   \ <-----push here
                 |     |
                  \___/

    Make sense?

	I recently swapped out all of the tube sockets from my 70's Twin
	Reverb. Along with changing out the resistors that were on soldered
	to the sockets. It was very time consuming (did only one at a time),
	but all of my weird noise problems (those that never last long, or
	come up at totally inexplainable times) went away - Same tubes were
	used afterwards, so it must have been the sockets. It took me about
	6 hours to all of the tube sockets (10 of them).

	The spray cleaner had been used extensively on the 12AX7/12AT7 sockets
	(not by me, but the previous owner), and this was probably the
	location of most of the problems. I don't know how to get into those
	sockets to tighten the clips, where the 6L6GC's sockets are much
	more accessable. I had problems where all of the tubes were working
	themselves loose over time also. If it's just one socket, go out and
	buy a bunch of spare sockets (you'll find them harder and harder to
	come by over time) and change out the bad one, You'll probably spend
	substantially less time overall, and the socket won't surprize you
	at a gig anymore.

								Jens

    
    
    	Bri, yer gonna laugh.... I use a tiny drill.. the end that would go
    in the chuck... I put it in a small vise grip (to use as a handle)...
    squirt the cleanin' goo all over the socket and drill... then I
    ummm.... insert and remove the little feller just as fast as I can..
    kind of like...  nah, you get the picture, right... I get a drill that
    feels like it will make contact, but that doesn't feel so tight that it
    will screw up the tensioning of the sockets.  And another thing....
    
    
    	While I'm on the subject of cleaning tips, I use a .45 caliber
    copper wire cleaning brush to clean dirty �" jacks... once again,
    plenty of cleanin' goo.. then in and out as fast as you can.  
    
    [;8) moo...

re: 264

Brian,

I support the prevous replies, go for a new set of sockets.  You may have more 
than one problem in that the metal connections within the sockets are usually 
plated when new and it is this that wears off with time. Cleaning will help 
short term, but due to the rougher surface due to wear it quickly picks up 
dirt and grime.

PS. a little trick you can try is to use a piece of fat string soaked in 
cleaner and use a piece of fuze wire as a leader to get it started (or try 
carefully poking it through with a stiff piece of wire ( I often use the 
internal wire from bin ties).

If you want to go the whole nine yards in cleaning, take the chassis out 
doors, place a rolled up newspaper ball under the socket in question, and 
tip small quantities of industrial trico (ethylyne ?) through each hole.

This stuff is mega ! *** but watch out for the fumes *** My first pargraph 
still applies though.....

Good luck !

Dave

	I'm trying to help a friend of mine discover some information about a
tube marked 7591.

Can anyone fill me in on the operating characteristics of this tube??

Especially bias conditions for class B or A/B operation??

Most importantly, does anyone have an old tube manual kicking around that they
would be willing to part with??


Thanks,
Steve
    

    Steve,
    
       You need look no further than our very own building -- go see Dennis
    Cline, resident tube guru.
    
    --Chuck

    I'm back, thanx to a friend who is letting me use his account, as they
    are hard to get here in Franklin.  I'll be posting often, and will
    still answer ??????, but please post them here, as I don't want to
    confuse my friend's mail file.
    
    Luv ya all....
    
    Jay Tashjian
    P.O. Box # 189
    Worcester, Ma.  01602
    
    

    
    
    Boy, it's great when this company does the right thing!  Returning the
    king of the tubes note to his rightful place! 8-)
    
    Kevin
    

    Maybe this is a trend !
    
    Scary

Yo jay welcome back!

dbii

    Just goes to show...ya can't keep a good noter down!

    I have a late sixties, silver-face Fender Deluxe Reverb amp.  The
    Tremolo circuit is failing.  It works occasionally, but just for
    a few seconds after the tremolo is turned on.   When it DID work, 
    the tremolo was very percussive.   The tube driving the circuit is
    OK.  Any ideas?
    
    Jim

>    I have a late sixties, silver-face Fender Deluxe Reverb amp.  The
>    Tremolo circuit is failing.  It works occasionally, but just for
>    a few seconds after the tremolo is turned on.   When it DID work, 
>    the tremolo was very percussive.   The tube driving the circuit is
>    OK.  Any ideas?

    Yeah, sell it to me cheap and I'll fix it. No, seriously, I'll
    check my deluxe schematic. Could be a resistor that's old and
    way off value and not allowing a capacitor to discharge. Anyway,
    Jay's back and he probably knows right off the top of his head.

    Hey Jay, good to hear from you again.

    -ron

    It's the opto unit right near that tube.  MDS has HD replacements
    for about $5.
    
    It is great to be back.  PLEASE (!!!!) do not send mail to this
    account, as my friend has a heavy work file, and although he won't
    say, would not want to weed out my mail.  Post anything here.
    
    What's coming soon?....a few projects, and a new contest!
    
    Luv ya all.
    
    Jay
    

    a little news:
    
    Fender has dropped all plans for more vintage amps.  No reasons why,
    but the fact that there are MANY 'new/old' Bassman's for sale used
    means something.
    
    Groove tubes new (Vol II) book is at the printers now.
    
    Gibson's new amps are neat.  Watch for their Vintage LP amp soon.  They
    bought a amp company in CA.  
    
    Richardson tubes now BUILDS a great KT88 tube, much better then the
    ones fron China.
    
    Ram tubes sells a 'KT99' which is a KT88 with a larger base.  A much
    better tube.
    
    Jay
    

    Hi Jay, good to see you back.
    
    Re GT book, I just got a copy of Vol III, which has a bunch of
    interesting catalog/ad reprints and a gorgeous color section
    of vintage amp/guitar pairs.  Anyway, is this the one you're
    talking about, or does GT have something else happening?
    
    /rick

>>    It's the opto unit right near that tube.  MDS has HD replacements
>>    for about $5.
    
    Where is MDS?  Do they do mail order?  Is there a minimum order $$
    amount?
    
    Jim

    Help.........Mr. Wizard....er, Jay Tashjian........HELP...............
    
    
    I'm considering a Plexi Park top...I've seen th 75 and 120wt tops...
    any opinions/recomendations/suggestions/recomendations/etc. one
    which one to go with (for tone, etc.) ?!?!?!?!?!?!?!?!?!?!?!?!?
    
    MUCH thanks in advance...
    Buck E Lee

    Hi Rick...yup, Voll III is the book.  Great job.
    
    ANY plexi Park top is good, if it works.  It depends on $$$$ and/or
    the source.  Who has it for sale...???  I'm curious.
    
    I'll get MDS's ### and post it soon.  They are in Chicago.
    
    Parks sound alot like souped up (gain wise) Marshalls.  They are
    fantastic.  The only thing is unless folks know the poop, they
    do NOT hold the value Marshalls do.  Please post who has it for
    sale.  My Fave-Rave source is Dynamic Sound in Conn.  GREAT folks.
    
    I'll be back later.  
    
    Jay
    

    Jay, I gather you are working in FXO. I also work in FXO. What
    shift are you working, and where is your office ? Look me up,
    and I'll fill you in on the various musicians working in FXO. 
    
    Mark

    I'm here in Franklin, 1st shift.  Office?  I'm just a scummy contract
    worker in FAI.   Although, as it seems that like all us contract folks, my
    days may be numbered.  So if I'm gone all of a sudden, don't be
    supprised.
    
    EVERYBODY send $28 & $2 shipping to GT for the new book (Amp book III)
    
    IF ya don't, you have no right to even THINK vintage.  600 pages of
    info, color pics, etc.   BUY IT NOW!!!!!!!  That's a order!
    
    THIS is just another reason why GT is worth supporting.  Besides
    great tubes, Aspen is truely devoted to his art.  Tell 'em I sent
    ya.  He DOES talk to the little people on the phone.  When he can.
    
    I've built 10 copies of my new tri-brid amp (tubes/transistors/Mosfets)
    and it screams!  I might have it out in limited numbers VERY soon.
    I'm working with a chain in NE now.  One, that although the name says
    otherwise, in NOT 'junky'.  Hint hint.  Nothing is signed/sealed/etc
    yet.
    
    BUY THAT BOOK!  And watch for a future article of mine in Glass Audio!
    
    Find me Danelectros!  Anyone got a Coral catalog?  I pay $$$$$$
    
    
    Jay Tashjian
    Sea Productions
    P.O. Box #189
    Worcester. Ma.  01602
    
    a.k.a. The Famous Ecclles (TFE)
    

    
|    EVERYBODY send $28 & $2 shipping to GT for the new book (Amp book III)
        
        I just  went  digging.    .  .couldn't find an address.  Does
        anyone have it at the ready per chance ?  Thanks. . .
        
        Well, just got  my  order  of  tubes  from New Sensor Monday.
        Dropped them into the  Sunn  and plugged it in.  Hmmm, what's
        that burbling sound ?   
        
        Lost a cap !  Oil  dripping  all  over  the base of the head.
        Still don't know if it was PCB stuff or not, so I was careful
        just the same.  
        
        Dug around with some of the electronic dealers we  deal  with
        here through DEC and found that nobody ever heard of  such  a
        strange  cap.     (Cornell-Dubilier  Cannister  type)  Values
        are/were.  .  .
        
        20 to 30 MFD  525 W.V. (half circle)
        15-to 20 MFD  525 W.V. (Square)
        15-to 20 MFD  525 W.V. (Triangle)
        15-to 20 MFD  525 W.V. 

        Finally  called  up  George  Kay  Audio  Labs,  INC.   in New
        Rochelle, NY.   They  do  repairs  and  modifications to tube
        audio/instrument amps.  The  guy  there  set me up with a few
        800 �f caps and said  he'd  send  a schematic so I could wire
        them up in series.  (They're  at  300 W.V.  and said that two
        in series with  a  couple  resistors would set me up near the
        525 W.V.) Something about  `hard  to  find'  electrolytics at
        that W.V. now-a-days.
        
        My only question, which I THINK he answered is, what will the
        increase  in the capacitance do to the signal ?    (i.e.    -
        bottom/top  end  ?)  Will  this distribute more energy to the
        tubes for a cleaner or crunchier sound ?  I have  a feeling I
        know  what  it's gonna' do to the bottom end, and it's gonna'
        give  an  earth  quake  a  run  for its money, but what about
        anything over 120 Hz ?    Should  I scrap my idea of a Harley
        and go for the Hartke cabs instead ? :^)
        
        Thanks. . .the Sunn is almost back in business. 
        
        Matt

    It rare I talk about other dealers, but watch out for George.  I, and a
    few friends tried to work a few deals with him, and (at least I) got
    burned.  He's a alright dude, knows his stuff, but not too bright
    business wise.  He sells doors and windows on the side.
    
    But, he's one great standup bass jazz player.
    
    About Sunns.  I have a old one, and will send ya the caps free if ya
    send postage to me (P.O. Box #189  Worcester, Ma.).  But , I'd suggest
    ya replace them with the 800MFD caps.  JUST WATCH OUT ABOUT TURN ON. 
    those caps are leftover stock from old NYAL Moscode amps, very old, and
    need to be charged SLOWLY !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!  Also, ya
    Sunn
    may NOT be able to handle the higer cap values.  BE VERY CAREFULL, and
    don't be supprised if it still blows up.  Sunns were never to strong.
    
    GT is in Sylmer, Ca.  Call info for the number (Area code 818), I don't
    have the number/address with me..sorry.  
    
    New Sensor tubes are ok, I've had no problems with them, I think ya
    problem was in the amp.  Daddy's in work has a 200S Sunn for $59!
    
    Worth it for parts alone.
    
    Still here...as of 12:55, 8-23-91.
    
    And DAMN...no one remembered my birthday 8/16.  Then again, I don't
    think I told anyone.   
    
    Looking for pity, I remain.......
    
    Jay
    

    
|    About Sunns.  I have a old one, and will send ya the caps free if ya
|    send postage to me (P.O. Box #189  Worcester, Ma.).  But , I'd suggest
|    ya replace them with the 800MFD caps.  JUST WATCH OUT ABOUT TURN ON. 
|    those caps are leftover stock from old NYAL Moscode amps, very old, and
|    need to be charged SLOWLY !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!  Also, ya
|    Sunn
|    may NOT be able to handle the higer cap values.  BE VERY CAREFULL, and
|    don't be supprised if it still blows up.  Sunns were never to strong.
        
        How much for the caps and how does one `slowly charge' caps ?
        At this  point,  I'll try anything, since I just replaced all
        the tubes.  I'll throw the old tubes back in for the power up
        though.
    
|    GT is in Sylmer, Ca.  Call info for the number (Area code 818), I don't
|    have the number/address with me..sorry.  
        
        Thanks Jay !
    
|    New Sensor tubes are ok, I've had no problems with them, I think ya
|    problem was in the amp.  Daddy's in work has a 200S Sunn for $59!
        
        Oh yeah, I knew it was the amp, I'd just hate to see that old
        work-horse sit collecting more dust cause I can't replace the
        cap.
    
|    Worth it for parts alone.
        
        Better yet, the Twin-Sunn's of the Outter Domes ! :^)
        
        Thanks again Jay.  .   .I'll  letcha' know what happens.  Too
        bad I can't send ya' mail though. . .
        
        Also, Happy Belated Birthday !
        
        Matt

    The only way to slow charge caps is with a variac.  Sorry.  Ya might
    try it with smaller voltages 1st (1/2 WVDC).  That was Daddy's in
    Shrewsbury, by the way.  My friend doesn't need to sort thru my mail
    every day, so just use my PO box (189 Worc., Ma.  01602)
    
    I didn't mean to dump on George Kaye.  He's really a nice guy, just not
    too wise business-wize.  He does know his stuff. ANYONE who designed
    the Moscode range of amps can't be stupid.  I just could not get the
    ommpp to do business with him, as his dealings ruined a really great
    deal.  Oh well, anyway send him money and buy his stuff.  He's NO
    ripp-off artist.
    
    Any ideas for a contest?  how about if ya send in 1 un-scratched
    lottery ticket to me, and the gift was a Marshall reverb-fuzz
    unit for the one who had the biggest winner?  HA Ha Ha.
    
    Then again, maybe I'm not kidding.  1 ticket per entry?  enter as many
    times as ya want?  Would Digital let me?  I doubt it.
    
    Any other ideas?
    
    Jay Tashjian
    
    (PS..no, I couldn't do it that way.  Unless Digital allows lotteries,
    which I doubt) (It was an idea only) (Do not send tickets)
    
    (Unless they are big winners...ha ha) ( no really, I don't want to po
    the powers that be.  I WAS only kidding) 
    

    Jay,
    
    I bought an old PV Artist 240 tube amp a few months ago. I need
    a footswitch for it; it's not yer basic footswitch! PV and local
    music stores haven't been terribly helpful. Could you build such
    a best for me? What course would you suggest I take with this
    problem?
    
    - Dave

    Footswitch's are no problem.  The hard part is finding the floor box,
    and deciding the ammount of wires needed.  Mail me a paper with what ya
    want it to do, what the connections are, etc, to my PO box (#189
    Worcester, Ma.  01602) and I'll build ya one, telling ya the $$$
    beforehand.  Try to have it JUST switch the amp, or the input, NOT both
    as mixing input cords and f/s corda are a hum no-no.  It should not be
    too hard.  IF it's just a replacement for the amp, tell me & I'll find
    ya one.
    
    News:
    
    Tubes from China have been failing BADLY.  The preamp 12AX7A are OK,
    but the KT88, 6L6, EL34 (etc) have been sucking EGGS!  AVOID THEM
    for now.  It seems that the factories need $$$$$ and are shipping
    anything.  A new KT88 is being built in the US (Richardson) and my 1st
    few samples have been tooth & nail in spec with the MOV-UK-GEC ones of
    old.  Big $$$$, but to us Marshall major users, well worth it.
    
    KT90/99's are still a great tube, although a bit high in price, but not
    sounding the same as the KT88.  More like a EL34.
    
    The GT EL34B is about the BEST EL34 around.  The glass is PURE lead
    crystal!  This may or may not have anything to do with the sound, but
    they hold up the best.   Remember, it's the EL34 'B'.
    
    But, then again, if ya bought ya new Tube Amp Book III, you'd know this
    already.
    
    Hiwatt is gone in the US.  A shame too.
    
    Orange was re-introduced on a limited scale, but MAJOR problems stopped
    that toot-sweet.  Smoke & fire, folks.
    
    Kramer, now just about dead, will never start selling amps.  Gibson
    bought the factory they wanted.
    
    Vox is sold in the US, but who cares, even the re-issue AC30 sucks eggs
    sound wise.  Buy an old one, fix it up.
    
    IF ya must have SS Vox, try Chicago music in Tuscon AZ.  They have ALL
    the old inventory.  Sane prices too.
    
    Till the next time
    
    Jay
    

    -1
    
    Thanx, dude!
    
    Man, what John Reaume is to Roller Coasters, Jay Tashjian is to amps!

    -1
    
    No, thank you.  I'm just a humble contract worker here who enjoys
    note-ing with all of you.
    
    And, I owe all I know to 2 folks...Jim Marshall & Leo Fender who got me
    into it, and thru their products, sparked my interest.
    
    Let me also not forget those folks at Digital who let me use their
    accounts, Vin & Joe.  Without them I would not be here now.
    
    And the good Lord for sustaining me.
    
    
    jay

    re: .291
    
    	Where is MESA getting their 6L6's these days? I've only been
    using older Sylvania's and whatever Peavey used back in 1985, but
    a couple months ago I really needed to bite the bullet and retube
    my Peavey MX amp and a friend recommended the Sovtek 6L6's. He also
    gave me a good price to boot so I tried them. I like them alot and turned
    my PV into a real animal. Would the Sovtek's be cool to put in a Mesa?
    Mesa likes to have everybody use Boogie tubes, BUT in reality will
    Sovtek's do? I do stay clear of GT's and Rat Shack tubes, but Sovteks
    in a Boogie? 
        Things that make ya go hmmmmmmm....
    
    			Curious Fred
   

    I think Boogie doesn't so much push using Boogie tubes as much as they
    push using "balanced pairs" (for the 6L6's that is).
    
    I.E. they sell tubes in matched pairs and claim that makes a
    difference.
    
    I like my Boogie sound so much I just keep using Boogie tubes (in the
    power section at least).
    
    If SOVTEK's are cheap enough, you could just buy them, try them out,
    and if they don't work, keep them as emergency spares.

I bought 16 of the Sovtek 6L6GC's 2 years ago (they were $7.50 at the time),
and I still have the first 4 that I put in my Twin Reverb running strong
(They get used for weekend gigging - and no-one says that I don't play
loud - I've been doing a lot of outdoors stuff this year). I had 4 of the
Chinese 6L6GC's, and had one fail within 6 months, so I keep the others
as spares in my cord case - the remaining 12 Sovteks that I have will be
used as needed. The Twin Reverb has a tub socket that is very near the 
output transformer, and the glass envelope on the Chinese 6L6GC is shaped 
different than the more narrow Sovtek. I bring this up because the tube
that failed (of the Chinese tubes) was in that particular socket, and I noticed
that the glass envelope would sometimes vibrate against the transformer -
this might have been why it failed. I replaced all of the tube sockets in my
Twin about the same time I swapped in the Sovteks - the tubes no longer shake
like they used to (they were not holding in very tight).

The Radio Shack 6L6GC's were made in Eastern Germany, and looked to me
Identical to the Sovtek 6L6GC. I had no problems with either. I have some
Phillips 6L6GC's also (the ones with the dual getter at the top),  I can tell
no difference between any of them.

I bought lots of 6L6CG's simply because I love sound of my Twin, and I really
want to be able to use it for a long time to come. One of my spare 6L6GC's
has a 1962 date on it, and it still works quite well (this one was out of
a Silvertone amp with 2 12" speakers that I played a lot in the 1960's).
The Sovtek tubes are affordable and let me keep my Twin.

							Jens

    I've retubrd a few Boogie's with the Sovteks, with no problems, and
    found that every one of the amp's owners loved the extra bite and
    smoother sound.  I's suggest them.
    
    On another note, I hit pay dirt this sunday.  While driving thru
    Westboro, I saw at a yard sale a Danelectro case, unopened.  I stopped
    quick, almost causing a pile up & bought a REAL Coral Sitar for $85!!!
    
    All it needed was strings!  Dead mint shape.  This is the old unit
    with the fake gator skin and drone strings.  AND, if that wasn't
    enough, the old lady asked me if I'd be interested in a "box" she
    could not lift upstairs that her son (who took of it seems years ago)
    used with the guitar.  WELL!  no lie, it was a tweed Twin, with
    controls on top!!!!!!!!!!!!!!!!!!!!!!!!!!!!  Near mint, no tubes, a few
    nicks!!!!!!!!!!!!!  After wetting my pants (sic) she said she wanted
    only $100 !!!!!  Well...I got my Bay Bank card, (just keeps getting
    better) and prayed I could withdraw the $$  I could.
    
    It's not for sale, I just added tubes, new sockets, and used some old
    GEC KT66 outputs and it sings sweetly!!!!!  This is without a doubt
    the BEST deal I ever found/heard of/dreamed of.  It may be hard to
    belive, but it's true.
    
    Needless to say, I stop at EVERY yard sale I see/hear of/dream of
    anywhere.  Next week I'm going on the road again.
    
    I just hope you all don't get there 1st.
    
    Still pinching myself to see if I'm awake...
    
    Jay Tashjian
    

    I'm sick (gleep!)

    I hate news like this, cuz it NEVER happens to me!!!
    
    8^(
    
    Buck, still reeling over the day his buddy from Berklee found a 
    mint 1962 strat at a yard sale in Northern Maine for $100.00.

        Jay, does  this mean that I can have your Sunn amp ?  Talk to
        me. . .I'll buy it !!! :^)
        
        Matt

    The only thing I ever got at a yard sale was smelly feet from wading
    through all the S%*T. Some people have all the luck. 
    
    Brian

To continue off of the subject (slightly)- If you see any guitar case, stop -
A lot of people put great guitars into junk cases and visa-versa. I often
pick up junker guitars (neck broken off, big gashes in the body) for $5.00,
only to find a Dimarzo pickup on it - worst case, you got a parts guitar.
Bridges, Tuning Keys, switches, hardware, etc.

Same goes for old tube amplifiers - maybe the speakers are still good, or
there is a bad tube in it (or someone lost the fuse cap - I got a mint
1957 (the date on the capacitors inside) beige fender reverb unit for $12.00
at a garage sale - nothing else was wrong with it). Lots of these are
trash, but you might strike a great deal that you find to be usable for
other purposes. The people selling this stuff don't know what it's worth,
and really just want to get rid of it. 

							Jens

    yup...I'll sell it...$35.   Write me with MO & shipping instructions.
    
    The twin does have one rubbing brown Fender speaker.  other then that,
    I still can't belive my luck.  I've gotten a few goddies in my days,
    but NOTHING touches this.  By the way, current value of the Twin is
    over $2k.  I wake up and look for it cause I still think I was dreaming
    the whole thing.
    
    In the bottom of the amp was a Electro Harmonix treble booster.  With
    the Coral sitar, the booster and the amp, I wonder what kind of music
    this guy played....???...
    
    Then again, I may not want to know.
    
    I remain, happy...
    
    jay
    

|    yup...I'll sell it...$35.   Write me with MO & shipping instructions.

        Thanks Jay. . .
        
        Matt

        I just remembered.  .  .I'll be  in  Worcester  this weekend.
        Will you be around, cause if so, Sunday's free  for me and we
        can  meet somewhere.  Either that or send me mail  with  your
        phone number.  I'll drop you a call. . .
        
        Thanks man !
        
        Matt

    Jay,
    
    I saw a P-word copy of a Fender tweed amp last night.  Looked neat,
    do you know anything about it?!?  
    
    Buck, who was curious

        Another quick question Jay. . .
        
        Would you  have  or know where to get a schematic of the Sunn
        100/200S ?  That would also be a blessing !
        
        Thanks. . .
        
        Matt

    
    	Jay, you old devil... I can't tell you how long I've been looking
    for a Coral sitar... I suppose it'll be a cold day in hell before
    you'll sell it... (and I wouldn't blame you!)
    
    	Any idea where I could find one? (No, I don't expect to get one 
    for same price!!)
    
    
    
    Brad Page
    

    Just saw a Coral sitar at Cambridge Music in Porter Square,
    for a cool $1200.  These babies are rare; to know of TWO in
    the Mass area in the same week is amazing.
    
    Hey Jay, keep making finds like this and you can retire.
    Is that Twin an 80 watter?  with MIDDLE control?
    
    /rick

    
    Yo, Brad!!! 
    
    Are you going to play a sitar in your country band?
    
    :-)
    
    guy

    
    
    
    	Jay, you wouldn't have a schematic for a 60s ampeg reverb-o-rocket
    would you... a friend of mine has finally got his going, but the
    tremolo ain't happenin'.. if you do, could I do that SASE deal for a
    copy of it??
    
    Gree Vee

    No problem on the schematics, just do da P.O. box thing with a sase,
    and a reminder of what ya want.  No charge, natch.
    
    It's a 85 watter, I don't remember if it had the mid.  I got news for
    ya all, they are not all they are claimed to be.  It IS a great buy, a
    neat collector item, but I got a black face twin that is a much better
    amp.  I MAY just sell this one for da bucks.  I've been offered $2k,
    which I feel is stupid.  BUT..a fool and his money....
    
    ANY amp is only as good as it was made in the 1st place, as I've found
    many tweed Bassmans that sound like crap, and is why ya can still find
    blackface Bandmasters & Bassmans for around $100.  BUT, a Deluxe, which
    is more or less the same amp, cost soooooo much more.
    
    I've found bad sounding Plexi Marshalls, and some 70's units that sound
    better.  It all depends on the animal in hand.
    
    I still think the BEST sounding amp is my (3) Marshall Majors (200
    watt) biased for Class-A, and the SVT with 6146 tubes.  But then again,
    I am picky.  And a little weird.
    
    No problem for Sunday, I'll be at Ken Chin's on Mill St drinking Scotch
    from 2-4pm.  Ask the bartender (Anne) to point me out, if ya can't
    guess.  I'm a regular fixture there.  For years.
    
    NOW..if I can just get on the Wrestling node, T.F. Eccles can post a
    few notes too.......
    
    Jay   (a.k.a. T. F. Eccles)
    

    Hey Jay...
    
    Any clue where I could pick up a AC30TB amp?  i *think* that is the
    model...the AC30 with the Top Boost.  Are they hard to find?
    
    B./

    Somebody help me out here, I can't figure out why anyone would *want*
    one of those Coral sitars. I didn't like the sound back then and I damn
    sure don't like/don't miss/wouldn't use it now. The only thing I'd
    remotely be interesested in would be the collectors value if i came
    across one like Jay. 
    
    "sakman"

>    Any clue where I could pick up a AC30TB amp?  i *think* that is the
>    model...the AC30 with the Top Boost.  Are they hard to find?

Hey Buck, going for that Brian May gig???  8^)

I saw an AC30 at Daddy's in Nashua last week, don't remember if it was a 
Top Boost or not. The price tag was somewhere in the $700-$800 range, I
forget exactly. Give'm a call....

alan

>Hey Buck, going for that Brian May gig???  8^)

    Yup.  8^)
    
>I saw an AC30 at Daddy's in Nashua last week, don't remember if it was a 
>Top Boost or not. The price tag was somewhere in the $700-$800 range, I
>forget exactly. Give'm a call....
    
    Yeah, I scoped it out while at the Pitrelli clinic last Tuesday.  It
    was just a regular AC30.  I need that extra edge.
    
    Buck

    That sounds pretty high on the price to me, are AC30s really going for
    that much these days?  The last time I looked they could be had used in
    the $350-$400 range!
    
    Greg (maybe I should have bought one back then and made a few bucks!)

    The top boost is that much, but it is an incredible sounding amp and
    commands the dollars as much as a Marshall does (probably more so).
    
    Only one I've seen in person is when Keaggy is in town.
    
    Mike

    
    From this week's Want Advertiser...
    
    1975 VOX Amp.  AC30 top boost with Celestion speakers. mint cond. 
    $1125 firm.  Providence, RI. 
    
    Send mail if you want the number, Buck.
    
    Kevin
    

    Well Buck, if you spot a good deal on a non-TB AC30
    (like at a yardsale in Westboro :-) don't pass it up.
    There's at least one mail-order kit for a top-boost
    upgrade, and at least one local guy who does em; it's
    not that big a deal.
    
    AC30s are cool but very delicate/tempermental and of
    course outrageously expensive these days, at least for
    the good ones.  It may be risky and costly to put one of
    these on the road; kind of like driving an old Jag.
    
    For people with an AC30 fetish, look into Matchless; a small
    west coast company that custom builds a killer amp using the
    best features of AC15s and AC30s.  They're advertised in the
    back of recent guitar mags selling their own hand-built
    replacement transformers for AC30s.
    
    /rick

	Thanks Jay. . .I'll be there Sunday !  Thanks again man !  I'm 
	FINALLY gonna' get that Sunn back up and  running !  (Found  a 
	Variac and someone that know's how to operate it too ! :^)

	Matt_PSYCHED_!

    As far as the sitar, it's a toy, a one horse trick.  I just always
    wanted one.  Jerry Jones makes a GREAT repro for around $700 street,
    and it's excatly the same.  Save, the bridge on his works better.
    
    WATCH OUT ON AC30TBR's!!!!!  IF it's a older unit, pre-Pr1mo Music (not
    a typo) it's worth it, IF it is a 70's-up, don't bother.  They are
    built like junk.  I know, I worked for Vox about that time, and 90% had
    to have MAJOR work done before they could be shipped to the dealer.  I
    find Dynamic Sound in CT has the best selection of Vox around, at
    non-ripoff prices.  Tell him I sent ya.  He has dead-mint ones, and
    some that "need a little work"....but, he's a damn fair dude.
    
    The Matchless amps are NOT real AC30's, but close, and very big $$$$$,
    but his head is in the right place.
    
    A simple test to check a AC30's age is the speakers...if they don't
    have blue "BULLDOG" speakers, it's a new one.  IF it doesn't have a
    tube rectifier, it's new-ish.  IF it hase Fane speakers, forget it,
    ditto Celestions.  This is not a rag on the speakers, but a way to
    date the amp.  $1000 & up can buy a 60's TBR in mint shape.  IF ya
    really want the bees' knees, and MUST buy new, Vox sold a few 
    "Vintage re-issue" units in Tan covering that retail about $900,
    and sound VERY good.  And remember, and old Vox (Even solid state)
    had Bulldog speakers.  They play a **BIG** part in that AC30TBR sound.
    
    They are worth it.  I own a piggy back TBR in dead mint, I bought it
    in the UK used for $500 with stand.  It screams bloody murder!  The
    only other I've seen is in the new GT book.  A great amp.
    
    I'll bring the Sunn.  Remember, it's as-is, worked the last time I
    plugged it in, no tubes.  Worth $35 by far.  I did do some mods
    in the PS, but you should have your amp running no problem, or ya may
    want to try this 1st. use ya old for parts.  MINE has reverb, etc. 
    
    Nah-nah...
    
    I'll have a schematic for ya too, IF I remember it...
    
    Bought a old Sound City 100 watt head for $90 yesterday.  Will buy a 
    Musicman 100 2-12 combo today for $125.  Gad, I love these cheap deals.
    
    Any Lab L11's or L5's out there?
    
    By the way, the AC30 in the want-ad is a 1974 model, way too much for
    the $$$$$
    
    Anybody got a schematic for the Mark IV Boogie?  MUST I call Ca.?
    
    Last year I bought a Vox Super Beatle in mint for $500.  I gutted out
    the power amp, and put a 'bast*rdized' Marshall output in it, and luv
    it.  It heats up something nasty, but sounds wonderfull.
    
    Still here, but awaiting the 'Axe'....
    
    Jay
    

    Jay,
    
     I sent you a SASE for a Rivera TBR-1M schemat a few months ago, did it
    get lost in the shuffle?
    
    dbii

    Nope, never did.  Try again, I'll keep a CLOSE look for ya SASE.   
    
    Sorry....
    
    Jay
    

    Not really tubes, but sorta related I guess.  Has anyone
    (Jay?) ever dealt with Lindy Fralin's pickup rewinding service?
    Are they still even in business?
    
    I've always heard (music store talk) that they were expensive
    but very good; never met anyone who actually used their services
    though.  I'm specifically interested in how "original" their
    rewinds are.
    
    /rick
    
    ps anyone check out the Peavey 4x10 Bassman re-issues yet?
    I've seen em in at Daddy's; Dave Hicks gave them favorable press
    in the GP "Bassman shootout" issue.  I took a quick test run;
    okay, but a ways from a Bassman imo.

    I've had a few pickups re-wound by them, and they are ok, better then
    some.  Big bucks, but worth it.  They are about the only folks who
    re-wind Gretsch PU's well.  They will do ANYTHING for a price,
    and talk says they never get returns.
    
    The PV bassman is ok, but not a 'Bassman' per say.  The covering is
    good, and I've always said PV was a fair deal for the $$.  ya gotta luv
    the beast to buy it.
    
    Jay
    

    Just a quick note to say goodbye, as the axe fell today.  I'll miss you
    all and hope to again post here at some later date.  I can ALWAYS be
    reached at:
    
    
    Jay Tashjian
    P.O. Box #189
    Worcester, Ma. 01602
    
     
    As Always, it's been a gas, and you Digital noters are some of the
    best informed around.  Please keep this note going, and take care.
    
    Special thanks to Vin for letting me use his account.  He's one of the
    good ones, who although had no interest in tube audio, did this out of
    the goodness of his heart.  
    
    I'll miss ya all.   BEHAVE yerselfs!
    Jay Tashjian
    
    A.K.A. T. F. (the famous) Eccles
    

        Good luck Jay. . .thanks for the info. . .and the amp ! :^)
        
        Matt

    The new Guitar World Buyer's Guide lists another Fender amp re-issue,
    a '65 black face Twin Reverb.  List price is $1199, so I'd guess retail
    to be somewhere around $800-$900.  At that price, unlike Fender's other
    vintage amp re-issues, you could actually find a real one in decent
    shape for less.

    	In the November 91 issue of Guitar Player magazine,there is 
    a pretty good article on vacumn tube's and about the best and
    most accurate article or information,I've seen for some time.
    
    							
                                        	Rick

    Guess who I spoke to toyay...
    
    Jay Tashjian!!
    
    I'm meeting him tomorrow, and he's going to try and bring the (once
    awesome) JCM 900 back to life!!  
    
    He wished everyone here well, and says "Hello".  He's only collecting
    amps now, and has about 7 Plexi's!!  One being a 75wt Red PARK, just
    like Aspen Pitman's!
    
    Yow!

I'd kill for that Park !!
   
Wow - A rare bird for sure !!

jc

    Gee Coop,theres a Park in Daddy's listing for $1200.....Head only..
    
    						Go for it!
    
    
    						

$1200 ?

Yeowch.

jc (Who can dream about owning a vintage amp...dream...)

    I met with our resident amp wiz, Jay T. today...here are some bullet
    items from the meeting:
    
    o He *may* be coming back to work at DEC in Hudson.  If he gets an
      account, he'll log in and say hello!
    
    o EVH had *nothing* to do with the design of 5150 amps.  Peavey gave
      him $5 million to put his name on them!  The contract is for a year.
      Eddie is still using two Marshall heads in his live rack for his
      tone.  Amps are "Ok, but still Peavey's" Jay touts... "They're not
      worth the money, and are not too road worthy"
    
    o The new Ampeg amps are being built by Crate!
    
    o ALL Marshall amps stateside may (probably) will be built by Korg in
      the very near future.  They are build a plant now for amp production
      over here.  Hmmm...  This could be bad quality-wise.
    
    
    more if I can think of it...
    

>    o The new Ampeg amps are being built by Crate!
    
    Crate has a new Quad type amp too now.
    
>    o ALL Marshall amps stateside may (probably) will be built by Korg in
>      the very near future.  They are build a plant now for amp production
>      over here.  Hmmm...  This could be bad quality-wise.
    
    Why would it be bad quality-wise?  The best guitars are American made,
    Boogie does quite well too.  If anything, the price may go down IF
    there's an export fee for the British.  I doubt a price decrease would
    happen though.  Once they lock you in, they got ya!
    
    Mike

    Could be bad quality wise ,.. cuz like any other company with a
    product,.. if you start spreadingthe company out too much across
    different continents and what not,.. the central quality control
    must be converted to "distributed" quality control,..Many companies
    screw up that transition,.. especially initially, and yet other
    companies dont' even think about it. Thats not to say that this is
    definitely going to happen to Marshall,.. but its one typical scenario
    of what could happen.
    
    							/Bill
    

    -1
    
    Exactly!  Right now, Marshall is Jim's baby.  WHo knows who might be
    reigning over here?
    
    And for yuks...look at the stateside built Hiwatt amps...pure and utter
    crap!!
    
    Food for thought...

        Hope the  lesson is learned from the VOX experience - when they
        were licensed to  the US, a real cheap transistor organ amp was
        badged to look like  the  AC30  and sold as "The Amp as used by
        the Beatles" across the USA.    Contributed in a big way to VOX
        going under.
        

    
    
    Think of the discussions we will have about English Marshalls being
    better/worse than US Marshalls!  Maybe Marshall will follow Fender's
    lead and call the US version something like "Marshall Classic" or
    "Marshall Standard" to really muddy the water.  Then the US version
    will change away from EL34's!!  The head of the US division will
    probably be a keyboard player!!  
    
    Kevin
      

I thought the "Old Marshall/New Marshall" thing was just when Marshall
shipped their heads to the US with 6550's ??

jc

Yeah too bad for Marshall, Korg is NOT a company that impresses me alot. And
since Yamaha bought them out I've got a feeling they got worse.

dbii

    It may not be too bad, after all, Korg already knows they got burnt
    selling units without EL34s in the past, I think they will have to
    keep the amp quality up or else lose sales to grey market imports from
    the UK.
    
    						Brian

    I'm not surprised by the Ampeg/Crate statement, after all, they're both
    owned by the same parent company, St. Louis Music.  
    
    re: US made Marshalls
    
    Seems to me that the quality discussion can only be wild conjecture
    until it actually starts happening.  
    
    re: Park
    
    There was one listed on USENET not too long ago.  I don't remember the
    price, but it wasn't as high as the $1200 one from Daddys mentioned
    earlier.
    
    Greg

	
	Greg's right - Crate and Ampeg are the same company! It's like
	the difference between Chevy and Olds.

	Isn't Korg the current US distributor for Marshall? I recon they'd
	want to build here to eliminate import fees and shipping expenses.
	This could mean lower prices on Marshall amps for everybody here.

	Now maybe Fender should open up shop in the UK?

    
      FWIW - That's why Yamaha, Korg, and Marshall were all in the same
    exhibit room of the trade show I attended. These are a great place of
    finding out what these alliances are.
    
    							-B()()M-

    BOY..It's great to be back, thanx to a friend's account.  I'm glad to
    see the ol' notes up and running.  A  few tid-bits:
    
    The US Marshall deal is in the final stages.  It's all based around the
    high import duty.  Jim SWEARS he'll keep the quality up!
    
    Yup, the US Hiwatts suk.
    
    While I've often dumped on Peavey, The NEWER EVH units are 1000%
    better!
    
    Bedrock (yup, Bedrock) is making one neat, strong amp at this time.
    
    I sold my red Park by the way for $3000!
    
    I'll be on again later...
    
    
    God, it's good to be back...
    
    Jay
    

    Hi Jay...
    
    Welcome back to GUITAR notes land!!
    
    Update -- My JCM 2500 is running fine these days...no problems to
    report.  Although, much of my 'burn time' is being spent on my new
    5150 amp these days...pretty burning tone!!
    
    You sold your Park?!?  I'm bummed you didn't call me first, but just
    as well, like *I* can afford a $3k head!!  8^)
    
    My next aqmp purchase will be a 100wt JCM 30th anniversary top.  Any
    comments on these buggers?
    
    
    Buck, a 100 watter man (once again) since the purchase of the 5150!

    Great to hear the amp is neat-o.
    
    The new jcm units are MUCHO better then the current Marshall units, I
    had one here last week, and they realy beefed it up.  A shame they
    can't do the same for the normal production units.
    
    I found 3 (3!) more Parks, which I bought in the UK.  2 red, one
    ultra-cool BLUE!  The 3 cost me less then 3$k.   I do not know if I
    will think of selling them.
    
    The 5150 is alot better then it looks, and IF ya like it, buy one.  IF
    you got any of the older units, and have problems (major), Peavey
    will REPLACE it with a current production model.
    
    I had one of the new Boogie 'Dual-rect' heads, and except for the fact
    it looks butt-ugly, it's made quite nice.  Too much $$$$.
    
    I'll be around...
    
    Jay....thinking up another contest....
    
    

    
    Welcome back Jay!  Which Bedrock amp were you referring to?  Also,
    your thoughts on the '63 Fender reissue Vibroverb?
    
    -pat

        Hi Jay !
        
        That Sunn  Sceptre  that  I bought off you is kicking great !
        Thanks again !  Got any more ?
        
        Matt

    Great to hear about the Sunn.  No, all Iwanna dump is a old Dyna MKIII,
    and a GREAT stereo TUBE reel-to-reel!  a Victorian model 600, dead
    mint, with factory UGLY mikes, manual, schematic, cir 1963.  it's
    un-modified and worth around $200.  This was owned by my Grand-dad,
    and is in perfect shape.  It takes NORMAL tubes, and would make a
    GREAT echo unit.
    
    IF you got enough $$$$$, Marshall will plate the chassis on the Anv
    amps in GOLD!  I'm ordering one.
    
    
    I got a line on a RARE AC-30X, with 2-15" speakers, TBR, and combo.  
    
    Bedrock amps are made in Southboro Ma, walking distance from Dec
    Shewsbury!  Nice people, and VERY well built.  Write them, tell 'em I
    sent ya and where ya saw me talking about it, the'll take ya for real!
    
    Yup, I'm going SS, and start building reverb/fuzz units mad for Tube
    amps, AKA the Marshall Reverb/fuzz.   Watch for it.
    
    Gotta go home & sleep.  
    
    By the way, some one wrote me and asked my taste in music..well, I
    really love OLD Zappa, Fairport Convention, and think Sandy Denny
    was the Greatest female singer who ever lived.
    
    But, then again, what do I have for taste???
    
    
    Jay
    

RE: Bedrocks

I think I've said this before, but I'll say it again.

I saw a guy with a PRS, a CORD and a Full Bedrock stack  - (2) 4x12's
and a head.  I was floored - what an EXCELLENT sound he had.

    Yeah, but was the cord pre-CBS?
    
    						Sid Gormless

I'm kind of under the impression that Bedrock has been
around for a number of years...  I dunno about Pre-CBS tho.
:)

jc (Who thinks it would've sounded BETTER with a PINK cord :)

    re: .356

>I saw a guy with a PRS, a CORD and a Full Bedrock stack  - (2) 4x12's
>and a head.  I was floored - what an EXCELLENT sound he had.        
    
    If you're thinking of that guy that was playing with 5 Live Engines
    when we saw them at that open mike night thing at Rack & Roll a long
    time ago, he only had a half stack.  The Bedrock head and a Carvin
    slant 4x12.  I will agree on the tone though, I was blown away!
    
    I hear he still uses that same rig, he plays with The Auto-No these
    days.
    
    Greg                  

Yep !  Thats him.  The AutoNo ?  Aren't they a lot more synth based ?
I thought Five Live Engines were HOT !

jc

    Yup, them Bedrocks are hot.  They are not big money either.  Made in
    the USA, in Mass., by musicians.
    
    They now make a Hiwatt clone that blows away the US Hiwatts.
    
    I need a response....would you folks rather see a fuzz/reverb unit in a
    rack mount case, or as a sort of mini-head like the Marshall R/F
    was...???   I dislike racks, but the cabinet costs $$$$
    
    This unit bleand a neg voltage in the signal path, mirrored as the
    signal's wave, and 'dances' with the - bias for the output tubes,
    so the R/F also (for lack of a better way of putting it) controls
    the output signal current draw.  This, for the same reason the 
    PNP FuzzFaces sound better then the NPN.  It really sings.
    
    I'll be back next week.  Maybe we'll get back into tube facts a bit
    more, and a few mods.  What do ya want?
    
    Jay
    

    Rackmount: modularity = flexibility
    

    >>Rackmount: modularity = flexibility
    
    ...and complexity
    
    8^)

    I've found that if you can find something that makes the sound(s) you
    want, you don't need flexability.
    
    Greg

    Exactly ..... if you only need 3 basic sounds, then 2 stomps will
    probably do ya.  But, to each his own ...
    
    Jerry

    Ya, that's how I think.  I really like the mini-head look.  Anyone who
    got my info pack way back then, and/or has a 1967 Marshall catalog has
    seen it.  It looks neat-o.
    
    A little news:
    
    Gibson will STOP building their 'gold' amps, because of lack of
    sales & big money prices.  NOW they're stuck with a amp company
    that builds x-pensive amps.  Sad.
    
    US Hiwatt's are NOT selling well, but my sources says they ( the
    company in Japan who owns, not builds them) will re-vamp them and
    try again.  Lotts-a luck.  What was once the most SOLID built amp is
    now junk.  Make the old UK ones worth BIGGGGGGGG!!!! money now.
    yuk-yuk.  I got 4.
    
    Fender is thinking of making Sunn brand guitar/bass amps again.  The
    interest is big, as Sunn PA's still sell.
    
    Kustom, as we know it, is gone.  Acoustic may soon follow.
    
    Remember Tusc?  They may be back.
    
    Oh well, gotta go home.   Bye-e.
    
    Jay
    

    re .-1
    
    >>Fender is thinking of making Sunn brand guitar/bass amps again.  The
    >>interest is big, as Sunn PA's still sell.
    
    they do? I've had a Sunn PA head on consignment in 2 different stores
    for 6 months and IT hasn't sold!!!
    
    - strapped for cash

    Yo, Jay...
    
    I saw some stuff on the new Gibson bass amp and it looks like a clone
    of the old AMP bass heads.  Do you know if Russ Allee of the old AMP
    company is working with Gibson?
    
    						Brian

    
    	Hi Jay - good to see you back here once again!
    
    	I have a request for information that may be of general interest
    also. How about posting some mA values for output tube biases - against
    various tube types, watts out and circuit topologies?
    
    	Like, say I have a 100W amp that uses 4 EL34's. What's the idle
    bias current setting through each one?
    
    	[This assumes the amp techn/musician can identify the cathode 
    resistor, can handle ohms law and has a meter or and can solder, for 
    the case where there is no cathode resistor.]
    
    	I can do _one_ myself; for a Dyna MKIII, there's an 11.2 ohm 
    cathode resistor which is sposed to have 1.51V across it. Ohms law says
    (I=V/R) there's 134.8 mA for this 60W amp using two 6550s. That's 67.4 mA
    per tube at the correct bias.
    
    	What I dont know, is what to set a 100W amp made up from 4 6L6's.
    50 mA per tube? They are a bit smaller than the 6550s...This amp
    has a 10 ohm cathode resistor for each pair of tubes, so, 100 mA
    through 10 ohms is 1 volt - so I look for a volt across these resistors
    to set the bias correctly. Sounds easy enough.
    
    	But - let's say I'm dropping in "KT90"s for more power, and, assuming
    the amp's power supply can handle it, what current do I look for to
    set the bias then?
    
    	Could you provide something like :
    
    	Tube	Number 	Bias/	Amp power

    	KT90	2	?	80W?
    	KT88	2	67mA	60W?
    	6550  	2	67mA	60W
	EL34	2	?	35W
    	6L6	2	50mA?	25W
	6V6	2	?	15W
    
        KT90	4	?	150W?
    	KT88	4	67mA	120W?
    	6550  	4	67mA	120W?
	EL34	4	?	100W?
    	6L6	4	50mA?	100W?
	6V6	4	?	 50W?

    	KT90	6	?	200W?
    
    	etc?
    
    	This would really help out the tube hackers around here ;')
    
    	Thanks!
    
    	Joe

    Woooo...it's 8Am, and I'm out of here.  But, sure no prob, I'll do
    a bit on it early next week.  
    
    Jay
    

    After doing a bit of thought, there is ONE main thing to think about
    when setting bias to tubes.  The AMP itself is the most important thing
    deciding bias.  You cannot set bias for current draw that is more then
    the power supply/power trans can produce.
    
    The BEST way to set it is with a scope, feeding a 1k hz signal into
    it, no dist settings yet, then adjust the bias till one gets the
    CLEAN signal scoped without hum or noise present.  THEN one can set
    bias for higher current draws (for kt90's, etc)
    
    Read the bias as you stated, use 25 watt resistors (MIN).  The only
    problem with doing it JUST this way, is it all looks good on
    paper/meter, but in real life, the amp may not be able to provide the
    current you are looking for.
    
    Gotta run, more tommorrow.
    
    Jay
    

    
    	Agreed that it would be a moot effort to find you've only tapped
    out the power supply in an amp upgrade to bigger output tubes.
    
    	Still, I think it'd be useful info to have on hand in the tube
    note. 
    
    	For example, it turns out that this "EARTH" amp I'm tuning up
    has 1 ohm cathode resistors per two tubes, which is a convienent
    value to work with for this 4 X 6L6 -- 100W output amplifier.
    I believe I measure 60 mV's for each pair of tubes, which is 30 ma per.
    I think I can turn them on a little HARDER with the bias control,
    but am unsure of the EXACT number I should look for - I mean er, 
    "stop at" for a 6L6 ;') I'm only getting around 75W out of it now.
    
    	Joe

    TUSC?
    
    Just say no!  8^)

    Don't knock Tusc, they were built VERY well.
    
    Max current ratings and nice med settings are:
    
    KT90:       230ma max               60-100 is normal
    KT88:       180ma                   60-85
    6550:       160ma                   60-80
    6L6GC:      140ma                   50-75
    
    Remember:  LOWER bias voltage = HIGHER current draw.
    
    Again, one can always heat it up a bit by lowering bias a bit.  I know
    of some folks who play the amp at the normal settings they luv for 
    a hour, then just cut back the bias till they can't cut it anymore
    without hum/3-order dist. (or till it sounds like crap).  This is NOT
    the best way to do it, but depending on the amp (EVERYTHING I've said
    depends on the amp it'self) it can work.
    
    ALL cat resistors MUST be 10 watt min, forget whatever I've said before
    or you see in the amp.  In my KT90 Class-A amp (200ma per tube) I use
    100 watt metal cased/heat sinked units.  IF the cat resistor fails,
    and opens up to 1 zillion ohms, kiss the tube and/or transformers
    bye-bye.  This is a BIG cause of problems with AC-30s.
    
    Any amp with a cat resistor runs while heating that resistor till the
    race is over, and whoever wins (the resistor dies, or the tube runs ok
    forever) depends on that/those resistors.  I use one cap/resistor
    per tube.  It works fine.
    
    Gotta run, see ya.
    
    Jay Tashjian
    P.O. Box 189
    Worcester, Ma.  01602-0189   
    
    (for those who asked for my address.)
    

    
    	Thanks Jay!
    
    	Say, can you tell us more about your KT90 based class A amp?
    Is is meant for guitar use? Sounds like the AC30 replica got a good
    review ("they couldnt get a bad sound out of it") wonder how your
    *AC100* would do?
    
    	Joe

Jay,

	There is a lot of Guitar magazine talk here in the UK between Aspen
Pitman of Groove Tubes fame and one Hartley Peavey.

Hartley says GT is all bull and he is conning the public in that matched tubes
can only be obtained by selecting what is on the market, and therfore it is 
not possible for Aspen to suggest he "tunes" metrics such as internal physical
dimensions etc.

Now, as a bit of a techie, but fairly thick when it comes to tubes, it would 
seem sensible to use matched bias sets, and maybe such things as mutual 
conductance, voltage gain, etc. 

Where is the truth ? People seem to think GT's sound much better, but is it 
hype? Is Aspen marketing soft tubes for profit ? (Hartley says....)

Interested to hear your opinion...........

Dave

    Hartley has also come out in print recently saying that tubes are done
    for by the end of the decade as they will be too expensive to use
    anymore.  Funny how Peavey has recently been pushing lots of tube
    amps, but that's what people want to buy, right?
    
    Hartley's main argument is that the small numbers of tubes used by
    guitar amps (vs. the huge numbers formerly used by all kinds of
    electronic gear until the 60s) will not support a modern tube
    production facility therefore the supply will eventually be either junk
    that you can afford or good stuff that you can't.
    
    I have to say I can buy his argument.
    
    						Brian

    I see his logic, too, but I think that if it applied, tube amps would
    be extinct long ago.
    
    You can't believe how many people I run into who are engineers (but not
    musicians) who can't believe that I just bought a new production tube
    amp.  They literally do not believe that any consumer product made in
    the 1980s, let alone the 90s, contains radio tubes.
    
    Agreed it's a specialized market but there are an awful lot of sockets
    out here in ampland, and more every day (judging by current fad).
    \Gary

    
      I can see the logic behind this as well. That is one reason why
    I'm hanging in there with my trusty SP-1000 power amp. Even though
    it's solid state, it still delivers (rulz!).
      The more popular tube types should be the last to go. My KH M5 that
    is powered by 6V6's is undoubtedly in more danger of extinction than
    my M1's that can use 6L6's OR EL34's. And I bet the 12AX7 preamp tubes
    have a long way to go. Their production cost must be relatively cheap
    and still have fairly high volume numbers. Look at ADA's new marketing
    approach for the Microtube power amp. It uses 12AX7's as the drivers
    for the solid state power stage, then they say "Real power amps glow in
    the dark!" Sort of misleading to me. Not to say it's a bad product.
    
    							-B()()M-

    But what are "high numbers"?  Consider that in 1960, an AM table radio
    had five tubes in it, a TV set had 20 or so.  And every household in
    the US had one or more of these things.  That's a *lot* of tubes, for
    which there is no further demand!
    
    Consider my own tube demand, I have four tube amps, and I use them
    regularly.  Over a period of thirteen years, I've bought less than a
    dozen tubes.  Sheesh, that isn't going to sustain anybody's factory!
    
    						Brian

    
    Re .77 and the price of valves (tubes). Having bought a valve amp about
    3 years ago I was feeling exposed in not having any spares to hand.
    
    Now I used valves extensively during an electronics apprenticeship in
    '69. At that time they were so cheap I didn't know how much they were.
    So, it came as a great shock when, for the first time in over 20 years,
    I went to buy a set of valves. I think I paid about 30 pounds for a
    single 6L6 and a couple of smaler ones. And these were cheapo ones as
    well!
    
    Richard

    Now, don't count out tubes yet.  With the Western USSR'ish countries
    now just tooling up for tubes, they will be around for a long while,
    and China is GOING TO GET IT RIGHT SOMEDAY as they have
    tooooooooooooooooooooo much money into it to stop.  AND, there is alot
    more tube stuff in Europe, etc., then here, as well as Japan.  AND,
    it will be a long time till musicians stop wanting tube amps.
    
    As far as Peavey/GT goes, I have been out to see GT, and know Aspen 
    well enough to know he ISN'T BS'ing.  He DOES match tubes in AMPS as
    well as on computers.  He may be high in price, but he DOES what he
    claims to do, with the promised results. Also, if not for *GT*, the
    ave. musician would know ZIPP-O about matched sets, bias, amp history,
    etc.  All Peavey has done is mass-produce.....rather well, but that
    is all.  I used to knock Peavey, but recent designs are VERY nice,
    and am suprised at all this talk.
    
    Jay
    

    There is also a thriving niche market in the high end audio realm
    for tubes.  Granted this is not a high volume market, but it exists
    and there's enough interest out there that they'll be in business
    awhile.  The prices these places charge would make Aspen blush however.
    The bottom line, you'll always be able to get tubes, but you may have
    to pay through the nose for them.
    
    /rick

    
    
Jay,


>    He DOES match tubes in AMPS as well as on computers.   


Reading his articles, he seems to infer he "does something " like perhaps 
hot-rodding. I believe all he does is buy hundreds and select them in pairs by
measuring and re-packaging. I do not think a GT tube is any different from any
other apart from that fact. I think he has built some measuring systems to 
analyse the tube as it goes into distortion and "match" or "select" on that
basis.

However, I do take the point that Apsen has done a crafty and successful piece
of marketing by providing the tube buying public with a matched set and 
"premium grade" sevice.......at a price!

I think the question I was trying to ask you was what are the parameters
that Aspen uses to "match" sets of tubes. Does he use gm ("slope"), gain, Ia,
or what ?

>    All Peavey has done is mass-produce.....rather well, but that
>    is all.  I used to knock Peavey, but recent designs are VERY nice,
>    and am suprised at all this talk.

Yes, I agree, his designs and manufacturing are world class. I would love
one of his "Bassman" re-issues".

Dave
    

    I don't retube my amp often, but reading the last few hundred replies
    makes me wonder if I'd have any trouble doing so.  It's an Ampeg B-25
    with 7199, 12AX7, 7027A and 5AR4 tubes.  I know 12AX7's are common;
    anyone know if the others are?

    Dave

    So YOU are the guy that owns the other Ampeg B25!!!!
    
    I re-tubed mine last summer. (Broke my heart, for the money I paid
    I expected more than 18 years out of a set of tubes...)
    
    Anyhow, I found all the tubes at the first place I looked (Union
    Music). All were GT except the 12AX7s, and the whole boat ran me
    about $100...
    
    Edd

        Hi Dave,
        
        I'm looking  at  Groove  Tube's book and according to this, the
        B-25 Ampeg takes:
        
                        2 x 7025
                        1 x 7100
                        1 x 7027 Duet (matched pair)
                        1 x 5AR4
        
        but the schematic  published in the same book shows the bottles
        you're talking about.
        
        The GT-7025s equate to 12AX7s (no problem there)
        The 5AR4 is a generic rectifier and is available
        The 7027's could be  a problem of sorts.  According to Pittman,
        this tube is out of  production;   he claims to have _some_ but
        you'll pay a premium I would think.  He also says to contact GT
        for a modification to take 6550s in  place  of the 7027s but it
        looks  like  some  electronics  work is needed apart  from  the
        inevitable rebiassing.
        
        Haven't got the books handy to check out the  7199  against the
        7100 - anyone?
        
        Andy
        

    I paid $60 for a pair of GT 7027s at a Portland, Maine music store
    (the name escapes me at the moment).  My Ampeg VT40 still doesn't sound
    as clean as I had hoped it would.  It doesn't sound at all right now --
    power supply problems that I haven't had the time to troubleshoot what
    with my involuntary relocation to Massachusetts, buying a house,
    coaching Little League, etc.
    
    Chuck

    re: Edd                                                      
    
    Yep, I'm the guy.  Funny thing is, I use it as a bass amp and it's a
    vanilla B-25, not a B-25B.  Overall, I have to say it's a servicable
    bass amp, loud enough for the small-club band I used to play in, but
    probably not the greatest bass amp in the world.  I can't say I've
    given it a fair test, though, 'cuz my homemade cabs sound like, uh,
    poop.  I have to tune them or get new boxes or something, but with this
    family-and-mortgage-in-suburbia business I don't play much.  Got to get
    those priorities straight.
    
    However, just this summer I tried playing some guitar through it and
    it's great!  I think with a couple of good twelves (and someone who can
    play) it's all the guitar amp I'd need for a long time.  And it's been
    super reliable - never let me down.
    
    Yours is a B-25B, and you use it for bass, right?  And where is Union 
    Music?  I live in Salem, NH.  Keep in touch.
    
    re: Andy
    
    My schematic (the amp came with one!) and the chassis itself both
    indicate the tubes in my reply.  I'd also like to know if the 7100 is
    the same as, or interchangeable with, a 7199.  It sounds like I should 
    pick up at least a pair of 7027's while I still can.  Thanks.
    
    re: Chuck
    
    Sixty bucks for 7027's?  <gulp>  Of course, it'd be even worse if I
    couldn't get them at all.  And considering that the amp's on maybe its
    third set of tubes in twenty years, I can't really complain.  Hmmm... 
    Maybe I'd better stock up before *my* kid hits Little League.
    
    Thanks, everyone, and keep the (Ampeg) faith.
    
    Dave

    Union Music is on Southbridge St. in Worcester...
    
    Yeah, mine's a B25-B with the standard issue 2 15" cab. Puts out a 
    walloping 55 W RMS. (But it's a FAT 55W!) I used it standalone for
    bass, then started using it as a stage monitor for my keys. Not the 
    best amp for that, but the cab made a convenient place to put my
    rack toys...
    
    I've got my receipt right here for the tubes...
    
               2 7027A      $40
               1 5AR4        25
               2 12AX7       30
                 ?????        4.80   (Coffee stain!)
               1 7199         9.80
    
    Edd

Dave,

    If you're willing to make your B25 "non-vintage" (and potentially
    change the sound), Jay Tashjian (lately incarnate as BUSY::VMESITE) has
    the info necessary to replace those 7027s with 6550s.  I don't really
    want to do the mod to mine -- I just want to get the damn thing working
    again.
    
Chuck

>    Union Music is on Southbridge St. in Worcester...
    
    I guess I'll look around a little closer to home first.
    
    You've got the Ampeg cab?  Doesn't that have Altecs of some sort? 
    A nice unit all around, and as loud as the amp is, the speakers can
    take the power without much distortion.
    
    I have to agree about the Fat Watts.  When I was in college I
    test-drove the B-25 up against a Bassman using the same bass, and 
    the Ampeg was noticeably louder (and fatter, and smoother).  I have to
    say, though, that the Fender had a nice tone.  I think today I might
    prefer the Bassman for either guitar or bass, but I also don't think
    it would have been clean at a loud enough volume to play in the band
    I was in back then.  The Ampeg is pretty clean until it gets right up 
    there.
    
    The Bassman was supposed to be 50 or 55 watts I think, so I used to talk 
    about "Fender watts" vs. "Ampeg watts".  On the other hand, the Bassman
    was a lighter head.  On the third hand, the B-25 has those nice shock
    mounts between the chassis and the box.  Maybe that prolongs tube life?
    
    Dave

    re: Chuck
    
    Yes, I've been reading this note and have saved Jay's addresses.  I
    don't care if it sounds "vintage Ampeg", I'm just interested in
    sounding good, whatever that means, and in saving money.  As long as 
    I can still get the tubes I think I'll just throw a set in.  But it's
    good to know that if the tubes do ever become scarce there is some
    recourse: refitting it with non-standard tubes.  Wonder what *that*
    costs?
    
    Dave

    At one point, Dave, I had considered modifying my Ampeg and got a pair
    of 6550s for $19.95 if memory serves.
    
    Jay, you have any power supply mods for the VT40 and other Ampegs like
    you had for some Fender amps?
    
    
    Chuck

    BTW - I've got the schematics for the B25-B if anyone needs/wants 'em.
    
    The bass cab is pretty damn big when compared to similar amps. It's
    close to the size of the book case here in my office. Back when I lived
    in a 2 room apartment, I laid it on it's side and used it as the 
    back of a stand for my Rhodes. (Talk about weight! A Rhodes on top
    of an Ampeg bass cab. I'm surprised it didn't end up in the apartment
    below me...)
    
    I've only had the back off once. Had to replace cannon connector for
    the head/cab cable. Must be 50 of those silly "torx" connectors holding
    it on...
    
    ...even still have the removable dolly and the vinyl covers.
    
    Edd

    re: Jay
    
    Thanks, Jay; that's what I wanted to know.  If I can find tubes I think
    I'll keep the little darling forever.
    
    re: Edd
    
    Yes, I've got the B-25 schematic, too.  But I bet no B-25* owner needs
    one, because we all have one!  And I agree about the solidity of these
    things, they really screwed them together.  And the weight - my drummer
    used to have some sort of Ampeg head that was about twice the size (and
    weight) of mine.  We didn't take that one to gigs.
    
>    ...even still have the removable dolly and the vinyl covers.
    
    You've got the covers?  I bet you don't even have any cigarette burns
    on the head!  :-)
    
    Dave
           

    > ...no cigarette burns on the head.
    
    Nope, and all the scotch stains got wiped off also!
    
    I reserved the headstock of my bass for butt-burns...
    
    ...used to run the thing with two cabs for awhile, one on each side of
    the stage. Damn bass just came from *everywhere*....
    
    Edd

>        Damn bass just came from *everywhere*....
    
    Hope you had roadies coming from everywhere, too.  :-)
    
    Dave

    What's best about Ampeg back then is, some of those B-## amps had
    little lite plastic logos.   IF ya bought one back then, you could
    of had a logo custom made! It stuck up in front of the tube cage,
    like a sign.  I had one made up from old NOS stock, now I just need
    a MINT amp to place it on.
    
    IF anyone wants reprinted lit from that era on the B-25, send me a SASE
    to my address (see past notes) and a note telling me what ya ask for
    enclosed.   I MAY even have a few 'yearly reports to stockholders' left
    I'll include free.  I raided a store once that kept ANY paper from
    companies forever.  I got all their past invoices etc from Ampeg.
    
    When I get back from the 4th, behold....a new contest!
    
    
    Jay  (glad to see 400 notes here)
    

    Just a quick note.....
    
    I've seen (as we all have) the notice about knocking 3-rd party
    companies.  It's a good idea, in a way, as they are not here to
    defend themselves.  BUT:
    
    IF I've P'od anybody/any company, I'm sorry.  I never ment to, never
    tried to, no one ever saw me, no one can prove I did..etc.
    
    My comments are my own, NOT Digital's, MINE (Jay Tashjian's) and come
    from DIRECT contact with the companies involved over a span of 20+
    years (I'm 37) and repairing them for that long.  I offer the chance
    to the companies to prove otherwise my statements.  Now, I've not
    gotten any heat from this, but I just want to protect myself, and
    Digital corp.  Nuff said......
    
    Besides, we do luv this stuff.  Why else would we be here?
    
    Gad, I wonder who is telling tales out of school?
    
    Jay Tashjian
     

    Jay - Is Ampeg still the same company it was back in the early '70s
    Magnavox days?
    
    Is my lifetime warrantee and 1/2 price speaker replacement deal still
    valid?
    
    Edd

    
    Ampeg is now owned by St Louis Music - that also brought you Crate.
    
    
    I think they used to be owned by Hartzell. Hey, I had one of those
    amps with the plexi lit logo - Portaflex!
    
    							-B()()M-
    

    So let me ask a question... if you had just bought a new all-tube amp,
    (Peavey Classic 4x10) and you planned on keeping it for a while... 
    It uses 12AX7s and (I forgot what, EL? maybe) power tubes.
    
    Would you buy a full set of tubes for it as spares 
    in anticipation of price or availability problems 
    in the future?
    Or would you wait until it needed the tubes?
    
    Do you relamp on a scheduled (preventive) interval?
    Or do you wait until a tube fails?
    What is the failure mode of a tube?
    (How do you know you need new ones?)
    \Gary

    Wait.

    Wait, but have a spare set handy.  They won't fail at home, always at a
    gig.  Murphy's Law ...
    
    Jerry

I concur...

jc (Who lost a quartet on stage once, and finished the night with a 
    Fender Champ.)

    .405  CAVLRY::BUCK
    > Wait.
    Why?
    
    .406  RAVEN1::JERRYWHITE 
    > Wait, but have a spare set handy.  
    In other words, buy spares?
    
    .407  KDX200::COOPER 
    > I concur...
    With what?  Waiting or buying now?
    
    And how do you when to replace them?  How long do they normally last?
    \Gary

No, sell it now and buy a nice reliable solid state unit that won't burn tubes
out when you least expect it.

:-)

When I bought my Kitty, Daddys just happened to be having a sale on Boogie
tubes (2 for 1) so I bought a full replacement set (12ax7s and 6L6s), plus a 
set of EL34s as alternates since it could use both types.  So (obviously) my
thinking was to have spares on hand.  I think it's a good idea in any case.
And yes, the price of tubes will only go up, and the availability will only
go down, and they don't go bad sitting on the shelf.

You can pretty much tell by sound when a tube is going bad.  (Or by looks:  if
it's not glowing when the others are, it's probably bad.  :-))  Gone are the 
days of tube testers in every drug store and Radio Shack, unfortunately.

I've still got tubes in my rig, but they're just in the preamp now.  And 12ax7s
are still pretty well available;  though I'm gonna buy more soon, "just to have
on hand"...

-- Sam

I bought 16 6l6GC's last time I bought tubes - I rather have lots of
spares than have to hunt for them later. I'ver only had one 6L6GC problem
since I bought these 3 years ago (The tube became Microphonic). I'd buy the
spares & pay for them now & not have to worry about it (the failure
was on a Chinese 6l6GC, the remaining 12 were SOVTEK's - I have 4 of those
in my Twin Reverb at the moment).

								Jens

>No, sell it now and buy a nice reliable solid state unit that won't burn tubes
>out when you least expect it.
    
    Absolutely.  And you can ship that nasty old tube thing to my house,
    willya?  It's junk, but I'll take it off yer hands for ya.
                                                              
>You can pretty much tell by sound when a tube is going bad.  (Or by looks:  if
>it's not glowing when the others are, it's probably bad.  :-))  Gone are the 
>days of tube testers in every drug store and Radio Shack, unfortunately.

    I seem to remember hearing that a bad *sounding* tube will often pass
    those "tube tester" tests...
                                
    Greg

EL34's burn up faster than 6L6's.  6L6's burn up faster than 6550's
(military tubage).

How long ??  I don't have an "hour" figure.  but I'd say EL34's in a marshall
will last you a year, if you play a lot.
jc

Groove Tubes have orange paint on them - when the orange turns brown,
you replace 'em (in theory)

    
    
    Buy 2 spare sets when you buy the amp...and get the dealer to give you
    a break on the price.  If you buy 'em later you'll have lost some part
    (maybe all) of the dealer's thrill of the amp sale...
    
    Why two sets?  Murphy, again...the only time a new tube is bad out of
    the box is when you NEED it.
    
    

    It's always good to have a set of spares if ya play out enough and 
    NEED the amp to work proper.  Pre-amp tubes at least you should have
    1 of EACH Pre-amp tubes.
    
    Another good thing about GT, da orange paint.  BUT any paint on a tube
    will shade darker IF they are run hotter then they should. Look at any
    AC-30 running class-a.
    
    Pre-amp tubes, when they start to die, turn gray-ish around the pins,
    this also allows ya to spot used tubes.
    
    Jay
    

    
    Is there a easy method (besides volume produced) to determine if an
    amp is running in class A or push/pull mode?  The reason I ask is 
    because the last time I had my amp apart I lost track of the switch
    position  - that is, the toggle switch can be reversed easily. 
    
    Thanks,
    -pat

    No, cause every amp runs class-a till it hits the bias cutoff point
    and turns to AB.
    
    It depends on the amp/circuit, etc.
    
    Jay
    

    
    	Jay, I am confused by your last reply.  I just want to verify 
    	my switch configuration.  It would seem that least an electronics
    	type could verify it by the schematics...
    
    	-pat

    Elderly, where I shop, carries Ruby tubes.  Is this a good brand?
    (Negative replies by MAIL, please.)
    \Gary

    Ruby tubes are good, a bit high priced, but not bad.
    
    I don't know what amp your talking about.  IF the amp has a Class
    A/B switch, it would change the bias voltage (lower - bias = more
    class-A) or it's one of those "quasi-class-A" amps.
    
    tell me what amp ya talking about, I'll reply better.
    
    OH, if we have to start sending mail to tell the truth about a 
    product, that will dampen things around here.  I'm against it.
    
    Jay
    

    Thanks for the Ruby tubes info.  Elderly had them so cheap I thought
    they were an off-brand (12AX7 $7~8, EL84 $9).
    
    AT THE RISK OF STARTING A RATHOLE......
    the notion of not posting negative comments in Notes files is Digital's
    idea, not mine.  It's a long story why this is.  I agree that it
    squelches honest negative replies (but we still have 'private' VAXmail
    for that).
    
    I _have_ seen instances, and continue to see them, where a vendor or
    merchant is bashed in Notes in an unjustified manner, and of course is
    not there to defend themselves.
    
    But the policy is as clear as any in Notes or at Digital... just ask
    your friendly neighborhood moderator. 
    \Gary
    We should probably take this to "General Discussion" so as not to
    clutter this topic... thanks again or the Ruby tubes recommendation.

    I believe the policy explicitly stated no negative comments about
    retail businesses.  I think honest equipment reviews are still fair
    game.  I never interpreted it to say "no negative statements about
    anything, ever".  But that's my personal interpretation and it might
    not be correct.
    
    Jay, I believe the amp Pat was asking about is a Kitty Hawk M1.
    
    Pat, why don't you just open it up and look?
    
    Greg

    
    	Jay, yes it is an M1 Kitty Hawk.  Greg, I don't know how to tell
    	what's what.  My switch got pulled out of the panel one day, and
    	I ain't sure if it's in correctly.  That is, the switch can be
    	replaced upside down easily.  Maybe I worry about lame shit too 
    	much, eh?
    	

    I say forget figuring out which way it's set and put it wherever it
    makes the amp sound best to you!  That way you get a sound based on
    your objective ear, not an ear prebiased thinking you'll like one
    sound better then the other...
    
    Greg

      According to the schematic, the A/AB switch not only lowers
    the bias for class A operation, but lowers the plate voltage for
    the output tubes as well ( down to 250 volts from 500 ).  So
    whichever setting of the switch is louder ( all other things being
    the same ) is probably the AB position.  Or, pull one of the output 
    tubes, stick a VOM + probe in pin 3, - probe to chassis, and flip 
    the switch while watching the meter. The higher reading concurs
    with the AB setting of the switch.
    
              Kent ( R/O noter )

    Yep, the last note is right.  I'll check my KH schematic tonight to
    see if there are any wire/color signs there.
    
    And, for the last time here, IF someone just bashes a company for
    whatever reason ("They suk") that is unfair, but if I feel that a
    company is not: a good buy for the $$, made shabby, sounds like
    crap, or has problems, I'll report it here.  
    
    We gotta go beyond the "Brand X rules, Brand Y bites" talking, and
    stick to reasons why.  In the long run, it should make a better set
    of notes.
    
    Just my 25 cents.....
    
    Jay
    

    while walking thru E.U. in Boston, I noticed a full pile on brand-
    new Marshall catalogs for the taking.  Also was the sheet by Marshall
    on 'hot-rod' mods.
    
    Marshall has DROPPED plans to build amps in the USA.  Good for them.
    
    
    Picked up a plexi 200 Marshall Major for $400 in R.I. last week. 
    Needed a few tubes.  Ya don't see many PG Majors around.
    
    Anyway, time to go sleep...
    
    
    Jay
    

    Just got some interesting lit in the mail, from Torres Engineering in
    California.  They're into a lot of cool stuff, but the main attraction
    appears to be custom amp mods.  Here are a few examples:
    
      Brown Sound Fender - convert a standard Fender into a full,
        ultra-hot Marshall.
    
      Boogie mod for Fender, Ampeg, Traynor etc.
    
      High gain "Metal-tronic" mods for Marshall or non-reverb Fenders
       (Bandmaster, Showman, etc.)
    
      Max Studio Princeton - and I quote, "more sound than you can
        possibly buy for any price".
    
    Lots more.  Mods are available in shop (you ship your amp) or also as
    kits.  The kit prices aren't terribly cheaper than the in-shop ones
    (example, Brown Sound Fender is $95 either way, so you basically save
    shipping to and fro).  There are tons of little mods (buffered efx,
    etc.) and even the big mods can be broken up into smaller sub-mod
    kits, so you can mix and match to your heart's content.  They even
    have mods for Carvins!  Lot's of other cool stuff in here too.  They
    publish these things called "Perfect Guitar" pamphlets, supposedly
    containing insider mods and tips for guitars, pamphlets on capacitors(!)
    (as in how to tweak up your guitar amp with them), stuff on alternate
    wiring schemes (this one free if you buy a pickup from them), etc.,
    andonandonandonandon... you get the idea.  If you're into amps, or
    guitar tweaking, they seem to have some interesting stuff.
    
    Jay, anybody, ever hear of or deal with these guys?   I'll post the
    address and phone; you can get a copy of the catalog and some other
    junk for free.  No, I'm not affiliated blah blah blah...
    
    	Torres Engineering
    	110 Avila Road
    	San Mateo, CA  94402
    	415-571-0849
    
    Have fun
    
    /rick

    Oh yeah, some tube prices from Torres:
    
    	Mesa 12AX7	   $6.40
        Mesa matched 6L6  $28.80 pair
    	Sovtek 6L6	   $7.95 ea
    	Sovtek 5881	  $12.50 ea
    	Tesla(!) EL-34    $18.75 ea (Czech tubes, hey the name at least sounds cool)

    Just FWIW
    
    	Daddys has 40% sale on tubes 'til the end of the month (Hope
    I didn't already post this :-)
    
    	I picked up a duet of EL34's for $24,.. and 3 12AX7's for
    $4.80 a piece,.. so I was able to retubr my entire Marshall
    50 Watt JCM900 Dual Reverb for like $38 :-) :-),..
    
    	I'm a very happy tone bro with these new tubes... and from
    what I'm reading,.. these are good prices,.. especially for Daddy's.
    
    	See other notes for my raves
    
    							/Billy
    
    
    				

    After reading about the great sale on tubes at Daddy's, I stopped by
    the one in Salem, NH, last night to ask about tubes for my Ampeg B-25.
    12AX7's they had lots of, but it seems they never heard of 7027A, 7199 
    or 5AR4.  The salesman said the ones on sale were Mesa Boogie tubes and
    MB only sold the ones they put in their own amps.  He knew numbers like
    6L6 and EL34, but that didn't help me much.  The 12AX7's really were
    were only $4.80, but that was the one I was least worried about.
    
    I think I'd better start looking for these things; they're only going
    to become harder to get.  FWIW, Daddy's is apparently not a Groove Tube
    dealer.
    
    Dave

    
    
    I also picked up a pair of EL-34s and some 12AX7s to use as spares for
    my Marshall.  But, I did note that the EL-34s are marked EL-34/6CA7.
    
    As Jay said...FACT: 6CA7 AND EL34 TUBES ARE *NOT THE SAME*
    
    What's the word on these Mesa tubes?
    
    Kevin
    
    
    

    The Mesa tubes I've seen in the past were 6CA7s (which were
    typically Amercian made), but given the volatile nature of tube
    suppliers these days Mesa may now be getting real EL-34s from some
    Eurasian supplier.
    
    The Czech made Tesla tubes are definite EL-34s; I've heard these
    are very rugged but not that good sounding.

    So how will they sound different?  Will they affect the longevity of
    the amp?
    
    Greg

    
    
    I have no idea on the difference between the tubes, but cruising
    through this note I also found
    
    
    >> WATCH OUT! many folks who sell what they call a EL34 may ship a 6CA7!!!) 
    
    Jay, can you shed some light on this?
    
    Kevin
    
    
    

    Perhaps I wasn't clear in trying to explain this in my previous note.
    The 6CA7 is an American equivalent to the European made EL-34.  Both
    tubes are pin and somewhat spec compatible, but will sound different
    due to different physical design and the small differences in operating
    specs.
    
    The European EL-34s (mostly made by Siemens) were relatively fragile tubes,
    but saturated quickly and nicely for overdrive.  American 6CA7s (Phillips,
    I believe) were more rugged, with a harder sound.  Note that the original
    EL-34s, built by Mullard and used in late 60's Marshalls, were themselves
    a bit different from the modern ones, more rugged but still with nice distortion
    characteristics; sort of an ideal cross between the modern EL-34 and 6CA7.
    You can still buy NOS (new old stock) Mullards for big bucks from specialty
    dealers; besides guitar amps, the EL-34 is a very popular tube with high end
    audiophiles!
    
    In the 80's, it was common when buying an EL-34 tube to actually be
    sold a 6CA7 (from Mesa, for instance).  These were considered
    electrical equivalents, and Mesa even touted the increased reliability
    over the Euro versions.  For most guitar heads, these were good enough.
    Connoisseurs and other anal retentive types (like me) however did notice
    a sonic difference, and sought out the real thing.  I have a late 60's
    Marshall with 20+ year old Mullards that sound better than any newer
    tubes I've heard.
    
    The current situation is that American and most (if not all) Euro tube
    manufacturers are out of business.  All new EL-34s are made somewhere
    in what was once affectionately known as the Eastern block; they mostly
    seem to be copies of the fragile, modern Euro EL-34.  I've not seen any
    Teslas yet, but have heard from others that these are somewhat more rugged
    than most.  The comment about not sounding as good... well, who knows?
    One man's poison...  They may, in fact, be a throwback to the old
    Mullards, which would be nice.  Mesa had an inventory of 6CA7s that will
    eventually deplete.  When that occurs, Mesa will start selling one of the
    Eastern bloc versions of the EL-34; maybe this is already happening.
    
    /rick

    
    
    
    Great info, Rick.  Thanks!
    
    Kevin
    

A lot of the following information is taken from an article in The Absolute
Sound magazine (july/august 1991) by Steve Melkisethian of Angela Instruments.
The intended audience is high end audiophiles, but the info is useful for
guitarists too.  I highly recommend this article (you can order back issues);
it's chock full of info on tubes, where and how to find em, and the current
state of the world supply.  Also, check out Angela if you're at all into old
amps and other tube gear; Steve's one of the major honchos of the vintage
tube world.  Enjoy.

  Mullard EL-34		Made till mid-70's, common in early Marshalls.
			Straight brown or black plastic base, spot welded
			superstructure (the metal junk inside), later types
			had slotted (3 slots) and crimped instead of welded.
			Usually says "Mullard" right on it.  Good sounding and
			reliable, a great tube for guitar amps.  NOS available
			for big bucks ($50+ apiece).
  Tungsram EL-34	Hungarian made, looks and sound similar to Mullard,
			also used in Marshalls (probably more recent) but
			cheaper looking and not as reliable.
  Tesla EL-34		Czech made, new tube, another Mullard clone but better
			made and supposedly more reliable than the Tungsram.
			WARNING: Mullards have been counterfeited by stamping
			the name on both of these tubes.  The lesson is, if
			you ever buy any NOS Mullards, know who you're dealing
			with!
  East German EL-34	Sold under names Telefunken, Siemans, ITT-Lorenz,
			Marshall, RCA, National and others.  Noticably skinnier
			than Mullard types, distorts easily (and hence desired
			by many guitarists looking for that sound) but low
			reliability.  Goes into runaway and thus may be the
			one of the major culprits in the effect know as
			"Marshall Meltdown".
  Japanese EL-34	Sold under Dynaco, Raytheon, and also counterfeit
			Mullard.  Looks like East German, except for three
			crimped slots and long spot welds on superstructure
			and dimple on top of bulb.
  American 6CA7		GE/MPD and Phillips.  Usually says 6CA7 USA on glass.
			Big bulb like a 6L6, supposedly not as sweet sounding
			as Mullard but better bass response.
  Chinese EL-34		Crudely cut reinforcing tab spot, crooked droopy glass,
			chalky solder seals on pins, avoid!
  Yugoslavian EL-34	EI or Magnoval brand, long nipple with seams on bulb,
			avoid!

    Wow!  Great info, Rick!
    
    Thanks!
    Greg

    Steve is about the fairest, most knowledgable (sp) human around when it
    comes to amps and tubes.  I've delt with him alot, visited him a few
    times, and he knows his stuff.
    
    The 6CA7 is a cross between a 6550 & EL34.  It takes longer to clip,
    and is a bit more ruggard, but I (and many others) dislike the sound.
    
    Those 'blue bottle' EL34's are about the best sounding around.
    
    By the way, there is another 6CA7/EL34\6550 clone, the 'coke bottle'
    6550.  A little faster to clip, but not as strong.  Then, there is the 
    6550 that looks like a KT88.  A piece of crap.
    
    Steves bit on tubes is a MUST for folks.  If ya really want it, write
    the usual way, enclose a few xtra stamps, and I'll send ya a reprint.
    
    Jay
    

 I would like to re-tube my Fender Champ 12 with something else
 than a 6L6GC (and without reliability problems for the amp).

 Any Idea ?

 Thx

    I've changed a few Champs to use EL84's, like Vox AC-30's.  I'll check
    the circuit, and post any changes.
    
    The Champ does NOT have enough current to run 6L6GC's well, and
    should be avoided.
    
    Jay
    

    RE: Champs
    
    I'm a little confused here...
    
    The amp in .441 is a Champ 12, which was designed to use a single
    a single 6L6.  Are you saying, Jay, that the Champ 12 design is
    not adequate?
    
    I can certainly understand that the older ~6 watt Champs would
    not be suitable for conversion to 6L6 or EL34 tubes.  
    
    What would be the advantage of converting one of the 6 what Champs
    to use an EL84 instead of a 6V6?  
    
    Jim

    What I'm saying is that to change from a 6V6 to a 6L6 SHOULD either run
    the new tube at a much lower then normal current draw or overheat the
    power supply because of higher current draw.  Champs over the years
    were fitted with various differant power transformers, some can 
    handle/dish out what is needed, some cannot.  I do not like, in
    smaller amps, to refit them with larger tubes, because of this.  Older
    Gibsona, Ampegs, and Wards/Supros are almost impossiable to work 
    this way.  The EL38 (6BQ5) was what I wanted to fit, but this 
    involves refitting new sockets, not too hard, but more work.
    
    IF you still want to put a 6L6 in, choose the smaller bottle, 5881
    styles.  NOT the larger newer Fender bottles.  
    
    The Champ is a adequate amp, with lots of guts, but when ya start
    asking it to do more then the design was made for, it will suffer.
    
    Glass Audio magazine a few issues back did a good work on re-fiting
    Champs with larger tubes, but they, IF I remember right, added a new
    transformer for 6.3 ac heater supply, thus relieving the old PT of
    it's heater draw, and then the PT can supply the 6L6 with no problem.
    
    Just my 2 cents.
    
    Jay
    

    For anyone buying one these ever-popular Peavey Classic (2x12 or 4x10)
    50-w all-tube combos, they take 3 12AX7 and 4 EL-84 (_not_ EL-34!!!).
    
    The 12AX7 are easy to find but the EL-84 (_not_ EL-34!!!) may take a
    while, especially when you have to keep explaining to people that they
    are _not_ EL-34s!!!   ;7)
    
    The ones I got recently from Elderly were Ruby tubes (allegedly
    matched sets) that were made in Yugoslavia.  They work.
    \Gary

    Are you telling us that if we buy one, we should prepare to
    re-tube right  away ??
    
    ??

    Ya should not have to.  The EL-84 Yugo is one strong tube, ALMOST as
    good as the old 'bugle boy' units from Amperx.  Rare these days.
    
    Jay
    

    re:  .446, which I assume is in response to .445 (re-tubing PV Classic)
    
    I bought the amp in May, my first tube amp.  Being a former Navy supply
    type (and Reservist of same), it occurred to me that the best time to
    be looking for parts that will eventually need replacement is NOT after
    they stop making both the unit and the parts for it.  So I decided to
    purchase a replacement set of tubes.
    
    I also found out that EL-84s were hard-to-find, which really gave me an
    incentive to spare them myself.  Thanks, Jay, for the tip in .447.
    By the way, I also do this "sparing" thing with other things I buy;
    the military term is "provisioning".
    
    Since I knew that the original tubes work, and rather than throw the
    Rubys in a drawer only to find out after 5 years that they don't, I
    figured I would install the Rubys and test them.  Once the Rubys were
    burn-in tested, I further figured that I may as well just leave them
    in, and save the PVs as spares.
    
    That's the logic.  No, the amp didn't need retubing after 4 months! ;7)
    Hope this made sense,
    \Gary

    Re: EL-84
    
    Are they really that hard to find?  I thought that they are
    interchangeable with the 6BQ5 and those are easy enough to find and
    cheap, too.  I have a pair of them in my little Traynor BassMate, the
    Mesa 22 Caliber also uses that tube.
    
    							Brian

    Who and where is Elderly?
    
    Dave

    If they're not in the "mail order sources" note, they have ads in
    almost every issue of Guitar Player.
    
    Greg

    Yes, the EL-84 is a one-for-one match with 6BQ5.  As a matter of fact,
    what I got were marked 6BQ5s.
    
    Compared to other tubes on the market, they are harder to find.
    At least they were for me.  And they weren't in _any_ catalog of
    musical equipment that I currently receive.
    
    They are also used in less applications, so unless more designers
    decide to emulate Vox AC-30 circuitry/tone, I do not expect them to
    become any easier to find.
    \Gary

    Elderly Instruments
    1100 N. Washington
    P.O. Box 14210
    Lansing, Michigan 48901
    
    Sales Floor 517-372-7880
    Mail Order  517-372-7890
    
    M-T-W 11-7 Thu 11-9 Fri-Sat 10-6
    
    "We Buy Sell & Trade New Used & Vintage Instruments"
    
    (reputed to be the world's largest Martin dealer)
    
    have mail order catalogs for acoustic instruments, electric
    instruments, amps, recordings, videos, books, and accessories
    at discount prices
    
    i live 1 hour from there and have traded there for 2� years and find
    them to be extremely knowledgeable and reputable --- i have bought 4
    guitars there and 1 amp plus assorted other stuff
    \Gary

    re: .453
    
    Thanks!
    
    Dave

 You can also use 7189 tubes.
 The 7189 is a stronger EL84.

 J.P.

    Another good brand of EL-84 is the Sovteks.  Steve from Angela
    recommends that you save your money and buy these instead of any
    high priced NOS tubes; he claims the Sovteks are as good as any
    EL-84 *ever* made.  Good and cheap.
    
    For a mail order source of the Sovteks, see my earlier post on
    Torres Engineering.  I'm pretty sure they sell em.
    
    /rick

    Thanks for all the tips on EL-84 sources!
    
    One question... in .455, J.P. says that the 7189 is a "stronger" EL84.
    Stronger in what sense?  (more durable, higher output, etc...)
    \Gary

    the 7189 is a Mil-spec version of the EL84.  SOME folks say it does not
    sound as well.  I've never used them, but will check them out.  They
    may just be a stronger spec (current, max plate voltage, etc) version
    OR they may have different guts, but the tube works the same way.
    
    The Sovtek EL84's ARE the best made.  As good as the old NOS stuff, 
    and besides, since 90% of amps that use this tube run Class-A, there
    is no need to match them closely.  They will just burn out at the
    steady pace till they die.  
    
    Jay
    

    OK everybody, get $3 out and a pencil....write this down:
    
    Eddy Electric Inc.
    60 Hannah St
    Staten Island, NY.   10301
    
    Now, everybody send that $3 to these folks, and ask for their 1992
    literature package.  Tell them I sent ya, and ya saw this in DEC
    Notes.  Why?  Well....
    
    For ya $3, you not only get their info on Hi-priced transformers, SUPER
    High priced caps, and the lot, but ya get pages of schematics from
    Japan of rare Class-A amps, using everything from 300B tubes to
    KT88s..& tech notes on why transformers work, and how.
    
    WELL WORTH $3 TO ANYONE WHO HAS ANYINTREST IN TUBES.  You will
    learn more in 10 mins then you could belive.  These schematics
    are not only had to get, but it would cost over $3 in copying
    costs alone.  Trust me on this one folks.......
    
    
    Jay tashjian
    

    	Hi, Jay:
    
    	Got a quick question: I own a 1965, eight-watt Rickenbacker amp.
    It's run by one recrifier, one 12AX7, and one 6V6. I've read that a
    single-ended 6V6 is unstable when driven hard, and I believe I proved
    it - the l'il beast died on me the other night. I'll troubleshoot it
    myself, and replace what's necessary. But, my real question is, what,
    if anything can I do to stabilize this bugger without ruining the amp
    for "collector's" purposes (you know, investment)? Or, should I just
    give up and play this one only at low volumes and leave it stock?
    
    Thanks,
    
    Bill Message

    Sounds like ya just got a bad 6V6...they should not die any quicker
    then say a 6L6.  Check ALL parts connected to the output tube socket,
    and replace them.  There should be a cathode resistor, replace it 
    with a MIN of a 5-watt unit.  Replace any cap attached to this
    resistor, and any screen power resistor (again, 5-watt...cap at a min
    of 50 WVDC).  Check power supply filter caps also.
    
    Hope this helps...
    
    Jay
    

Q: for Dr. J:

   I am currently working on a '59 Bassman reissue. It origially had a bad
6L6GC that was blowing the fuse. I also swapped in a spare output transformer.
Anyway with that fixed, I was curious if you could give me some hint on a 
power-up issue/non-issue:
   The tube(V5?) that I replaced, briefly turns blue on power-up (approx 1/2-
second). It is only on that tube. Anyway, I think that the source of the surge
is from the B+ voltage after the standby switch. The choke is right after.
The only other thing I can think of is that the 470-ohm screen resitor is 
somehow bad. I measured the resistance and seems to be good... Any hints?
Is this a real problem?

Thanks!

   John D'Errico

    
    I may have answered my own question (below).  I checked the voltage 
    coming from the Class A Class A/B switch and it read approx 250 v in
    Class A versus 500 v in Class A/B mode.  That should tell the tale,
    right?
    
    -pat (with one hand in his pocket, err, you know what I mean) 
    
    ;^)
    
           <<< KDX200::SYS$SYSDEVICE:[NOTES$LIBRARY]GUITAR.NOTE;1 >>>
                              -<  Guitar Notes  >-
================================================================================
Note 1994.416                  TUBES, TUBES, TUBES                    416 of 463
RAVEN1::BLAIR "Belay that nose picking, Cadet!"       8 lines   7-JUL-1992 07:28
                             -< Class A or A/B??? >-
--------------------------------------------------------------------------------
    
    Is there a easy method (besides volume produced) to determine if an
    amp is running in class A or push/pull mode?  The reason I ask is 
    because the last time I had my amp apart I lost track of the switch
    position  - that is, the toggle switch can be reversed easily. 
    
    Thanks,
    -pat

    That is correct.

One question :

 Could an abnormal output xfmr overheat be due to an
 unmatched set of output tubes, or is there an other
 reason ?


 J.P.

    I'm not sure what you mean by an abnormal output xformer is? Typically
    output tubes are the weak link in the power section and are more
    prone to failure than an output xformer. Keep in mind that the
    output transformer is also called a impedance matching transformer
    and so I would check you speaker load.....
    
    
    							Rick
    

    If the transformer itself is overheating, the primary may be carrying
    too much current.  Check the bias on the output tubes, or, better
    still, if possible, check the output tubes' idle current ( current
    at no signal ).  

>    If the transformer itself is overheating, the primary may be carrying
>    too much current.  Check the bias on the output tubes, or, better
>    still, if possible, check the output tubes' idle current ( current
>    at no signal ).  

Also, make sure that your loading is correct. Tube/Transformer amps can take
direct shorts, but have a great deal of difficulty with impeadance loads
that are  not correct (like 32 ohms when it's expecting 4 ohms, or an open
circuit & no speaker load - this could fry it).

								Jens

    Jay asked me to tell the notesfile that his temp job at
    DEC has ended, so please don't try to reach him via EMAIL.
    His address is 
    
    Jay Tashjian
    P.O. Box 189
    Worcester MA 01602

I have a question (2 actually):

- Whats a 6V6 power tube look like?  Does "They're short, almost as short
  as a 12AX7" sound pretty close??

- Whats the output power ? 15wts?

Thanks,
jc

    Actually Coop, 6V6 is a symbol that Masters and Johnson used in their
    books to describe this position that when two people......oops, wrong
    conference......
    
    
    ;)

    
    
       A 6V6 is bigger than a 12AX7, it looks more like a scaled down EL34.
    I think the 15 watts a tube thing is accurate to a certain degree. 
    My M5 45 watter has four 6V6's. My only real complaint about the M5
    at all is that the potentiometers stink (noisy as all heck!). As a
    matter of fact that was KH's biggest problem, nobody likes the sound of
    a noisy pot.
    
    							-B{}{}M-

    In a Class A/B Push Pull amp the maximum-signal power output is 10 to
    14 watts for a 6V6.(two tubes) Single tube 4.5 to 5 watts....
    
    
    							Rick
    

Hmmm...

I ask, because I'm looking at buying Jerry Whites Laney ProTube Combo.
He's not sure what kind of tubes it has, and he's not sure how many watts 
output it has.  

He was pretty sure it was a 60wt combo, but Pat Blair has a 60wt KittyHawk 
M1 that eats it's lunch, so he thought maybe itt was a 30wt combo.

Anyone know anything about Laney ProTube combos ??
jc

    Hey Coop,
    
    	There was a PT30 with 6V6's,PT50 with EL34's(2) and a PT100 with
    more EL34's(4).... 
    
    							Rick
    

Excellent info!!  So the ProTube 30 had (4) 6V6's or (2) ??

Thanks a lot dood !!

jc

    It had 2 6V6's and was probably 30 watts class AB push/pull
    
    Any amp running properly with EL 34's will be louder....such as the 
    Kitty Hawk stuff.....
    
    							Rick
    

    Note that you can get 30 watts out of a pair of 6V6s, but you have to
    exceed the operating voltage specs of the tube to do it.  Blackface Fender
    Deluxes pushed this boundary as did the legendary Jim Kelley amps.
    If the Laney is running them this hard too, you need especially strong
    tubes.  Ruby's from China (black opaque bottle) are the only current production
    tubes I know of strong enough to run this hard without blowing up real fast
    (old NOS RCAs work great too).  Any idea what brand of tubes are in
    there?
    
    /rick 

 I would like to add a Penthode/Triode switch in my
 Fender Super-Amp (50/60W 2x6L6 in Push-Pull).

 My first idea is the following :

    -------------------
   3|                 |
   ====               |
   ----               |
   ---- 4---          |
 5 ----    |          |
  /====\   \470 1W    |
 8         /          |
           \  T       |
           | / o------------/
           o/               \
             ! o-- P        /
             !   |      A+ -\ OutPut Xfmr
             / o-------     /
           o/    |    |     \
           |   o-|    |-----/
           \     |    |
           /     |    |
 8\====/   \470  |    |
   ----    |1W   |    |
   ---- 4---     |    |
   ----          |    |
   ====          |    |
     |           |    |
     ------------------
                 |
                 B+

 Note : the T/P switch is a double inverter !

 - In the T position, the two G2 grids a connected to the
   plate thru the 470 resistor (Triode connection)

 - In the P position, the two G2 grids a connected to the
   B+ supply thru the 470 resistor (Penthode connection)


 I have three questions :

  - Is it a good design (?!)
  
  - Should I increase the 470 resistors wattage
    from 1W to 5W for example ?
  
  - Does the Triode mode impact tube life time ?


 Thanks in advance.

 J.P.

Is this really what your suggesting to do? Eliminating the use of a plate 
in the tube?
                                                            
    ------------------- Output transformer
   3|                 
   ====               
   ---- 6--------|    
   ---- 4---     |    
 5 ----    |     |    
  /====\   \470  |    
 8         /     |    
           \  T  |    
           | / o-------B+
           o----           
             ! o---Ground?        
             !         
             / o-------B+     
           o----          
           |   o---Ground?    
           \     |    
           /     |    
 8\====/   \470  |    
   ----    |1W   |    
   ---- 4---     |    
   ---- 6--------|    
   ====              
     |              
     ------------------ Output Transformer
              

  Not at all !. I don't think the 6L6 grid2 will survive ......

  I just want to disconnect 'hot' point of the 470 resistor
  from B+ to connect it to the plate of each related tube.

   Look at my drawing (I know, it is a poor character cell drawing...),
  the plates are still connected to the output Xfmr. 
  I just want to switch the pin4 (grid2) from the B+ to
  the plate (thru the 470R).

  Another question :
   - Does the bias change when switching Triode/Penthode ?

  Regards

     Check .82, Jay says to use 200 ohm resistors, and if you can
     devise a way to wire it up, I don't see how it wouldn't work.

     Neal

    Neal's right even though you might want to look at a similiar
    design to verify the wiring....
    
    The b+ on a Fender super comes to P6 on the 6L6 through the 470 to
    P4 is what was confusing to me in your drawing.  
                                                    
    
    								Rick
    
    

    
    I have done this on an old GUYATONE Fender(ish) clone and it works
    fine.
    
    Kept the 470 ohm resistors, just switched between anode or B+. 
    Wouldn't like to throw the switch while running though ( never tried it
    ).
    
    Used 5 watt resistors ( good idea even if you don't want triode mod ).
    
    No change to bias in my case.
    
    Nick

    
    
    	I recently picked up a Fender Bassman cheap and would like to check
    the biasing. I seem to recall a note in this conference that described
    how to bias a tube amp. Could someone please point me to this note, or
    possibly enter the procedure. It would be nice if we had a general
    procedure that could be applied to all tube amps.
    
    Thanks 
    -Bruce

     Bruce,
     To bias your Fender Bassman amp, you'll need:

A) signal generator
B) voltmeter
C) oscilloscope
D) 50 watt 4 ohm dummy speaker load (100 watt is better)

1) Unplug amp
2) Pull the power tubes
3) Plug amp in and power on
4) locate power tube socket and measure voltage from pin 5 to chassis (gnd)
5) locate bias pot inside chassis and adjust to largest negative voltage (~-62V)
   (tubes are now over-biased, will run cool with lots of crossover distortion)
6) turn power off and put tubes back in
7) set generator to 2000Hz sinewave, use meter to adjust output to ~150mV,
   plug into normal channel (volume=off, treble=10, bass=10, bright=on)
8) plug in dummy load and put scope probe across the load
9) turn power on 
10) look at the scope and slowly turn volume knob up to 70% output or just
    about clipping. You'll see a somewhat distorted sinewave with a notch
    in it as it passes through 0. See figure A
11) adjust bias pot until wave form is a clean sine as in figure B
     
Fig A    /---\		      	   /---\
        /     \	      BAD 	  /     \
       /       \	    	 /	 \
      /	   	\		/	  \
   0 - - - - - - -- - - - - - -- - - - - - -
          	   \         / ^
          	    \       /  |______ crossover distortion notch
          	     \     /
          	      \___/

Fig B    /---\		      	 /---\
        /     \      GOOD    	/     \
       /       \	       /       \
      /	   	\	      /	        \
   0 - - - - - - - - - - - - - - - - - - -
          	  \         / 
          	   \       /
          	    \     /
          	     \___/

     Hope this helps

     Neal

    
    re .487
    
    Thanks for the procedure. BTW, why do I need a dummy load? Couldn't I
    use a 4 or 8 ohm speaker cab, and put the cab in a closet to save my
    ears? Also, would this procedure work on my 50W Marshall JCM900?
    
    -Bruce
    

    Hay Jay,
    
    My 5150 is too fackin loud for the small slubs I'm playing of late.
    If I yank the two outer output tubes (to half the wattage), does
    that puppy need to be re-biased??  Please advise before I yank em.

    
    Buck, I don't think Jay's around these days.....
    
    Kevin
    
    
     

    WAaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
    
    
    ANyone with a clue, then??

     Hey Buck,
     Yeah, when ya pull a couple of tubes, ya gotta re-bias to make
     things right.

     Sorry dood
     Neal

    Waaaa, how am I gonna do this?!

    Sure Buck, I'll take a stab........lessee, if ya pull out 2 of the
    toobs, duz ya hafta bias the ones that's left?   Uh, lessee, you'd be
    lookin' fer a yes or no......hmmmmmm, uhhhh, I say, eenee, meenee,
    minee, moe.........aw h*ll, I haven't the foggiest.
    
    Would it hurt anything to go ahead and re-bias anyway?  Safety
    method....
    
    Dawg

    Not to be contraire...but I don't believe a re-bias may be necessary,
    at least, not for the sake of tube or transformer safety.  You may 
    wish to check for crossover distortion with your signal generator
    and 'scope ( you do have this stuff lyin' around - right?  ;v) and
    maybe tweak the bias slightly.
    
    What WILL change is the output impedance.  If you have a 4-ohm speaker
    cab, set the amp's output impedance switch to 8 ohms.  When you pull 
    two tubes from the p-p primary side, the effective impedance of the
    output stage doubles.  This reflects through the secondary winding
    as well.
    			-Kent
    

    -1
    
    Thanks, I think?!
    
    For one thing, I have NO equipment ... scopes or otherwise!
    
    Secondly, I'm running 1 16ohm cab ... if I yank two tubes, are you
    saying ohmage would be 32??

RE: Buck 

I think thats correct.  You could re-wire your cabs though (probably, right?).

jc (who just knows to watch them filter caps!)

    Hmmm...yep.  You need a 32-ohm tap.  Or haul along your second cab 
    to give 16/2=8 ohms load so's you can use the 16-ohm setting.
    
    The same suggestions are given in The Tube Amp Book, BTW, in the
    Marshall amp discussions ( getting 50 watts out of a 100 watt head ).
    
    Probably the most practical thing would be rewiring your cab, as 
    suggested in -1.  You could install a switch to give yourself a 
    choice of 16 / 4 ohms so you wouldn't have to rewire it everytime 
    you pulled/reinserted your output tubes.
    
    			-Kent

     Re - .496 

     Kent,

     >Not to be contraire...but I don't believe a re-bias may be necessary,

     I don't see the difference between "a slight adjustment" and "re-bias".
     But if you don't at least check it, you could have a loss of the higher
     frequencies, depending on how wide the notch is. The wider the notch,
     the lower the frequency cutoff. What happens is that all frequencies with
     a wavelength of 2 times the width of the notch and shorter (higher freqs)
     are killed in the notch, and the ones below can be effected badly. The
     lower the frequency, the less effect the notch has, but the distortion is
     still noticeable. An amp slightly out of bias will lose it's "presence",
     and twiddling the presence control doesn't change much. You might be
     thinking you gotta go out and buy new tubes. But, then again...
     It could be 'cuz yer deaf, huh Coop?....Coop?......COOOOP!!  %^) %^) %^) 
     
     >What WILL change is the output impedance.  If you have a 4-ohm speaker

     Yeah, sorry about that Buck. Like they said, re-wiring the cab to
     4 ohms is your best bet.

     Neal

    How does it work when I use the Hi/Lo power switch on my amp? It shuts
    two of the 6l6's off, but I don't need to rebias. My guess is that the
    output is shunted but the tubes are still in the circuit. Yes?
    
    "sakman"

    I thought most of those power attenuation switches changed the power
    tube configuration between pentode and triode instead of actually
    removing some of them from the circuit, but I could be wrong I'm no
    tube techie.  I do know some of the manufacturers use different
    techniques.
    
    Greg

    Re - .500
       Yeah, I guess a 'tweak' is a re-bias.  What I meant is that the 
    >safe< bias level is the same for 2 or 4 tubes, since the anode 
    voltage doesn't change. So there is no worry about overloading tubes
    or smoking output transformers, from a bias point of view.  Slight 
    differences in tube characteristics make it desirable to check the
    'notch' from a TONE point of view.  But, lacking the equipment, you
    can simply pull the tubes, run the amp, and see how it sounds for
    yourself...
    
        Re - more recent notes - there are different methods for power
    reduction.  Mesa-Boogie has a switch that opens the cathode lead
    of two of the output tubes ( same as pulling them ).  Musicman
    amps actually selected different values of B+ for different power
    output levels.  Kittyhawk changed B+ AND bias to go from AB1 mode
    to A mode.
    
        I don't have a Mesa Boogie amp so perhaps someone who does can tell 
    us if there are considerations, output-impedance wise, when switching
    from 100 watt to 50 watt mode ( it seems to me there should be, as
    previously discussed ).
    
    			- Kent

     >safe< bias level is the same for 2 or 4 tubes, since the anode 
     >voltage doesn't change. So there is no worry about overloading tubes
     >or smoking output transformers, from a bias point of view.  Slight 

     The fact that the anode voltage doesn't change has nothing to do with
     the bias. The negative bias voltage on the grid has to be adjusted
     correctly, not because tone is the factor, but because if there isn't
     a large enough negative voltage on that grid to limit the plate current,
     the tubes would get real hot, and in an extreme case, go into meltdown.
     Too large and tone will suffer badly. If you pull 2 tubes, the load
     on the bias circuit changes, and would affect the 2 remaining tubes.
     Sure, you might not smpke anything, but is it worth it if it screws
     up the amp?

     Neal

 >    The fact that the anode voltage doesn't change has nothing to do with
 >    the bias. The negative bias voltage on the grid has to be adjusted
 >    correctly, not because tone is the factor, but because if there isn't
 >    a large enough negative voltage on that grid to limit the plate current,
 >    the tubes would get real hot, and in an extreme case, go into meltdown.
 >    Too large and tone will suffer badly. If you pull 2 tubes, the load
 >    on the bias circuit changes, and would affect the 2 remaining tubes.
 
    Tubes operating class A or AB1 by definition draw no grid current,
    and therefore present no load to the bias supply.  Pulling 2 tubes
    should have no effect on the bias supply voltage, and the 'per tube' 
    idle current should stay the same with 2 or 4 tubes.  The tubes 
    shouldn't run any hotter or cooler.  But I haven't seen a 5150
    schematic, either.  I know the above applies for Fenders, Marshalls,
    and most other amps that use grounded cathodes.
    
    

 
     Maybe pulling 2 tubes should have no effect on the bias supply in an
     ideal amp, but I'm assuming that these amps are far from "ideal". Right
     now, that's the only explanation for what I see on my scope. Any ideas?
     I always thought these amps were all class B. I suppose I could fax you
     a schematic to take a look at and you could tell us what they are. I'd be
     mucho interested. They do have grounded cathodes, is that the key?

     Neal

     I'd be happy to check it out, but I don't know where the resident
    'FAX' machine is...perhaps someone else here knows...Coop?
    
    What exactly is it that you are seeing on your 'scope?
    
    I am unaware of any commercial guitar/bass/keys/PA amps that use
    class B circuitry ( tube amps, anyway ), 'tho that doesn't mean
    there aren't any.  Might be fun to build one and see how it sounds....

    Re: class A
    
    Huh?  I also thought most tube amps were class B.  Class A is more hi-fi
    but gives lower output power and draws more idle current.  The only
    class A guitar amps I can think of are the Boogie Simul-Class amps,
    that put out 100 watts class B, 30 watts class A?  
    
    ??????
    
    						Reddy Kilowatt

Kent, 

Check with Doris in Personnel - I've used their FAX before.

jc

    No, .507 is right.  Audio tube amps are most commonly biased to run
    class AB1 or AB2; the bias point is somewhere between true class A,
    where the entire peak-to-peak signal is in the linear region of
    the tube, and true class B, where 50% of the time the tube is in
    cutoff.  With class AB2, the tube is in cutoff for at least a small
    portion of the time (<50%), so these *HAVE* to be used in push-pull
    configurations for audio; otherwise, you would literally cut off a
    small portion of the signal each cycle.
    
    I think the reason that you don't see class B audio amps is that,
    although you are still reproducing the whole signal each cycle in
    a push-pull setup, the reproduction gets very non-linear near cutoff
    (i.e., you would always get distortion in the power section).
    
    /rick

    Some of the confusion, I think, just comes from that fact that people
    tend to equate push-pull with class B.  The two are totally separate.
    You can run class A biased tubes in a push-pull configuration if you
    want.  Another problem is that amp mfgs and magazines have tossed these
    terms around rather haphazardly.

     >What exactly is it that you are seeing on your 'scope?

     Check out my lousy artwork in .487 for an idea of what it looks
     like.
    
     >there aren't any.  Might be fun to build one and see how it sounds....

     Geez, even Bri....er Reddy K thinks that these amps are Class B, we
     both can't be crazy can we?? Uh, forget I asked that question OK?

     BTW, these amps be strictly low tech and sound best when beating the
     snot outta them........huh Reddy? %^)

     Neal

    Actually, they are class AB1.  Brief primer:
    
       
         CLASS                          DESCRIPTION
    
           A                            Plate current flows at
                                        all times ( 360 degrees ).
                                        Typically no grid current flow.
    
           B                            Plate current flows 50%
                                        of sine-wave cycle 
      					( 180 degrees ).  Grid
    					current is drawn, so driver
    					must supply some power.
    
           C                            Plate current flows less than
                                        50% of sine-wave cycle ( 120
                                        degrees typical ).  Grid current 
                                        flows.  Used at radio frequencies;
    					unsuitable for audio applications.
    
    
       Between 'A' and 'B' we have:
    
           AB1                          Plate current flows for over half
    					but less than all of a sine-wave
    					cycle ( between 360 and 180 degrees)
                                        No grid current flows.
    
           AB2                          Plate current same as AB1.  Grid 
                                        current flows.
    
    
        In the AB2 and B cases where the grid current flows, the preceding
    amplifier stage must deliver power.  This is difficult with resistor-
    coupling and usually a transformer is used.  Triodes are used almost
    exclusively Class B.  The great power sensitivity provided by most
    beam tetrodes ( 6L6GC, 6550, EL34, KT66-88, etc. ) makes grid driving
    power unnecessary in commercial amps.  
    
    
         The Mesa-Boogie Simuclass is 30 watts class A; 100 watts 
    class AB1.  ( And actually the 100-watt setting has one pair of
    tubes operating AB1 and the other operating class A simutaneously-
    hence its name ).
    
        Kent  ( old tube dude )

    Oops, .513 was in reply to .508!  Lots of traffic while I was 
    composing the reply......

    For what it's worth, I checked a Mesa Boogie schematic for an amp that
    is very much (at the output stage anyway) like a Twin Reverb, i.e. same
    driver stage, a 6L6 quartet. The circuit does contain a switch labelled
    60/100 that opens the cathode to ground connection on 2 output tubes.
    Except for the value of the series grid resistors (2.2K as opposed to
    1.5K) nothing else appears to have been changed from the classic Fender
    design.

    As far as impedence mismatching goes, everytime someone plugged an
    extention cab into the extra jack of a Fender amp, there was a mismatch.
    If I understand the issue correctly, this situation is equivalent to
    running an amp with twice the speaker compliment.

    The question is, how much power is dissipated in the xformer with that
    sort of mismatch and is that enough to burn up the xformer at hefty
    power levels? At modest volume levels, I wouldn't be too worried about
    it. But if you crank a square wave through it at full volume even though
    the amp is running at only 1/2 power, I'd want to make sure that the
    output xformer can handle it first.

    At a minimum I'd suggest experimenting by putting the amp on a bench
    with the equivalent loading, running a -10dBm square wave into it,
    openning up the volume pots and monitoring the temperature of the output
    xformer with your hand.

    --Ron
    

    Yeah, Fenders were designed to tolerate a certain amount of mismatch
    and there are usually no ill effects from running the extra cab.  The
    rule of thumb is, never exceed a factor of 2.  For instance, you don't
    want to run a Deluxe Reverb, which is designed to drive a single 8 ohm
    speaker, into a 4x10 Super cab, which is 2 ohms.
    
    The Mesa power section is pretty much a direct copy of a Twin.  Note
    that on a 100/60w Mesa combo you actually NEED the extension cab to get
    full power in 100w mode.  At 60w, with only 2 output tubes enabled, the
    Mesa is designed to deliver full power into an 8 ohm load, i.e. the 12" speaker.
    If you kick in the extra tubes, the output impedance changes and the amp wants
    to see a 4 ohm load.  There's an impedance mismatch into the 8 ohm speaker,
    and you deliver much less power.  These combos are only truly 100w with a
    2nd speaker plugged in.
    
    Marshalls, on the other hand, have taps on their output transformers, so that
    they can always be ideally matched to different speaker loads.

    Ah HA! Clever aren't they those boogers.

    BTW, once upon a time when I had an abundance of 10" spkrs and a derth
    of twelves (around '72), I loaded my old Deluxe with 2 10s and built an
    extention cab of the same dimensions for another pair of 10s. I ran the
    Deluxe with that 4x10 configuration in my R&B band for over a year of
    steady gigging in small clubs. I guess I should consider myself lucky
    that the amp only LOOKS bad, huh?

    --Ron

    RE:496
      Buck,
       Apologies, etc.  You don't need to rewire your cab(s).  I
    fogged out and stated the impedance change rules wrong. Here's what
    you REALLY need to do:
                          # of tubes       impedance        speaker 
    			  in output         selector        cab impedance
    
      normal mode
      ( 100 watt )            4               16                 16
    
     
      modified mode
       ( 50 watt )	      2		       8  		 16
    
    
       This is the reverse of what I said earlier; sorry 'bout that.
    If anyone is curious as to why it works this way, I'll post the
    logic in another reply.
    				-Kent		

    -1
    
    You sure now??  8^)

    My last note is exactly as stated in the Tube Amp Book Vol III.
    I reviewed it last night.  And did the mental gymnastics to 
    convince myself that the book's process is correct. And got
    a headache     ;v)
    
    Yeah, I'm sure...

    re: .517
    
    You can get 8 ohms from 4 8-ohm speakers if you wire them series/parallel.
    
    Dave

    Ahhhh, but maybe I didn't.

    regarding triode vs. pentode:

    I noticed in the Guitar Player 100W Combo Shootout that most of the
    models featuring a triode/pentode switch claim that this offers 50% vs.
    100% power modes. But in .82 Jay claims that triode mode brings the
    poser down about 25%. Anybody know if these manufacturers are doing
    something different like maybe the switch also lowers the B+ or
    something?

    --Ron

    The latest GP features a letter from Jay Tashjian. It's vintage Jay all
    the way.
    
    Danny W.

    Re: .523
    
    What did he say?  I don't buy GP anymore...

    I forget even what the topic was, but it was like Life Imitating Notes.
    \Gary

    Maybe we shoudl ALL write in there and start bantering about
    Clapton and Toob amps ??  :-)
    

    My Traynor BassMate started blowing fuses on the gig last night (first
    problem I've had with it in ten years).  Symptoms: a note here and
    there would drop out, output seemed weaker than usual.  I already have
    a schematic and I pulled out the chassis this AM and looked for bad
    wiring (didn't spot any).  Power supply is my first suspect.
    
    Question: If I remove all the tubes will the power supply voltages
    marked on the schematic be off due to no loading?  
    
    						Brian 

    Probably.  The voltage just at the secondary of the input transformer
    will be correct, but anytime the supply voltage passes through a resistor,
    there will be voltage drop when current is flowing in the circuit. 
    You'll see these drops reflected in the values on the schematic.  Take
    out the tubes, and current doesn't flow through the supply lines, hence
    no drops.
    
    /rick

Brian,

   You can probably leave the preamp tubes in. First pull the power amp tubes
out. The first thing to do is check the voltages. The power valve plates should
be the highest voltage - between +300 to +500 Volts DC. The screens are 
generally a little lower in voltage.
   Also check to see if you have a bias voltage. This should probably be about
Negative-30_something - depending on the tubes. You probably have 6CA7/EL34's.
If you are still blowing tubes, pull the other tubes. If this doesn't work, you
may have a shorted filter cap, bad transformer, or rectifier. You need to 
isolate the power supply sections.
   If those seem ok, put in a set of new power tubes - including an inverter 
tube ie; 12AT7?.
   

Biff A. Roono

    Followup to .527:
    
    Why I fuc*ing love tube amps.
    
    My problem was a defective power tube that was arcing.  It had less
    than 20 hours on it.  In fact, the tubes I replaced were in there for
    the *ten years* I've owned the amp and were old when I got the amp. 
    Sonically, they were fine, but I decided that since I was going to
    start using it on gigs again (after a year of semi-retirement), I
    should pop some new tubes in it to be safe.  The result of this
    preventitive maintenance: the only time an amp has gone down on me on a
    gig *ever* in *fifteen years* and a waste of $25.  Oh yeah, I bought
    good old Mesa tubes (made in USA). @#$%^&&*
    
    So I popped in the old tubes (which I kept around as emergency spares
    and everything is AOK.  Except now I should go buy some new tubes
    *again* because I doubt the old tubes are gonna last forever.  Sheesh.
    
    							Brian

    
      A friend of mine has an old tube Marshall 2 X 12 50 watt combo.
    It must be at least 15 years old. He's gigged steadily and never
    replaced a tube until about four months ago because the amp started
    sounding ratty. He's definitely from the "If it ain't broke, don't fix
    it" school. 
      I'm still getting the old KH M5 power amp section ready to mount in
    my 1 X 12 combo (it will be mated to the REXX 610S preamp). I've had
    that project on hold for awhile.
    
    
    								-B{}{}M-

The last time I bought tubes, I bought Sovtek's (I find them to be excellent).
I had a Chinese 6L6GC start arcing on me after 7 or 8 months, and I tossed it.
I carry 2 spares of every tube the Twin Reverb Uses, and other than this
one instance, It's the only problem I've had in the last 8 years of owning
and using the Amp (We did an outdoor thing at Old Colorado City's 'Territory
Days' & I enjoyed cranking up the Twin - It's usually only played at
smaller clubs - I love that tone - used my '64 Gibson SG with the P-90
soap bars. We played both Saturday & Sunday late mornings).

I suggest that you track down sources of Sovtek tubes and try them. They
aren't matched, but, then I've never bothered with matched tubes & I
have no problems.

							Jens

    I got to spend some time with the "living legend" of tube amp repairs,
    Jay Tashjian, today. We mostly traded war stories about famous (or
    infamous) tube amps we've all known & loved.
    
    I was able to get some nice old Marshall & other catalogs & a few other
    interesting items & schematics. 
    
    The guy is even more amazing in person than in notes when it comes to
    tube amp knowledge. I expect I'll be staying in touch with him once
    I've recovered from losing sleep by staying up reading all this stuff !
    
    He said to let everybody know that he's still alive & well but hasn't
    been at DEC for some time. I believe his PO Box address still works if
    anyone wants to contact him.
    
    Paul

Can you repost a pointed to Jay's address?

Jim

    It's buried somewhere in this note:
    
    Jay Tashjian.
    P.O. Box #189
    Worcester, Ma.  01602
    
    Paul

    
    
    Anyone know the difference between a 12AX7WA and a 12AX7WB?
    
    Kevin
    

>    Anyone know the difference between a 12AX7WA and a 12AX7WB?
    
     I asked Mike Matthews and he said that the WB is much less noisier,
     especially in high gain circuits. The WAs are ok in my Fenders.

     Neal

    
    
    Thanks, good info.  -Kevin
    

    
    
    In case you are wondering, New Sensor's SOVTEK prices are as follows:
    
    
                5881/6L6 $6.90  
                EL34 $9.50
                12ax7wa $3.60
                12ax7wb $3.90
    
    
    Kevin
    
    

     Kevin,

     How recent is your price list? The one I have is from March '93.

     Prices are:
    
     Sovtek 5881/6L6WGC	$7.25 ea + $1.50/pr for matched sets
     Tesla EL34		$7.60 "  "    "      "    "      "
     Sovtek 12AX7WA 	$4.35
     Sovtek 12AX7WB 	$5.60
    
     Neal

    
    
    The prices are from September '93, Neal.
    
    Kevin
    

     Hey Kevin,

     Funny, I was home yesterday morning when the phone rang, and it
     was "El�n" calling from New Sensor. He's going to send me the
     new price list. The Tesla factory closed so New Sensor will be
     selling the new Sovtek EL34G for $7.50.

     Neal

    What's the difference between an EL34G and a regular EL34, Neal?
    
    Greg

>    What's the difference between an EL34G and a regular EL34, Neal?
    
     That's what I asked the "El�n" guy on the phone. He said that there
     is no regular EL34. There's only one Sovtek EL34 and the G is just
     to distinguish it from the Tesla EL34 that they're still selling until
     the stock runs out forever. I asked him if it had the same weird base
     as the Sovtek 6L6, and he said it looks like the old Mullard EL34. Neat.

     Neal-tubes-for-brains

    
    
      I knew there was a reason they put the 6L6/EL34 switch in my 
    KittyHawk M1's. It was just a matter of what tubes would be in
    production. I do remember the KH service manual saying the 6L6's
    were more reliable.
    
    							-B{}{}M-

    
    
    
    I got the tubes from New Sensor.  The final price was less than I
    expected.
    
                    SOVTEK
                    EL34 $8.90
                    12ax7wb $3.40
    
  Kevin
    
    
    

    A couple of queries:
    
    1. Can anyone confirm whether Jay Tashjian is still reachable at this
       address?
    
       Jay Tashjian.
       P.O. Box #189
       Worcester, Ma.  01602
    
    2. Is the "Tube Amp Book IV(?)" by Astrid Pittman only available by
       mail order in the U.S. or can you buy it across the counter in
       guitar shops?
    
       I know it's available in the UK, but I've got a friend who's going
       to the States fairly soon (probably before my next trip to the UK)
       and I guess it'll be quicker (cheaper?) to ask him to pick up a
       copy.
    
    Many thanks,
      Dom
    

     re: -1
    
    Do I take that as meaning "no", or simply "dunno"?
    
    Apologies for the apparent lack of patience, but it looks like the guy
    I was referring to will probably be leaving for the States this week.
    As for the Jay Tashian query, I reckon he's most likely the only person
    on earth who can tell me something about Davoli amplifiers ;-)
    
    Dom
    
    

    Yes, Aspen's latest Tube Amp book is available over the counter.
    (just tell em Guido sent ya :-).
    
    Btw, I read a review recently; they say if you've already got the
    last one (#3), look before you buy.

    Well, Dom, Jay used to make offers like, "I'm cleaning out my files;
    send me a SASE and I'll send you a bunch of vintage literature."  So I
    did once, to that address, and never heard from him.  I don't know what
    that means; however, my letter did not come back "Addressee Unknown".
    
    Dave

    re: .549
    Great, thanks a lot. No, I haven't got Vol. III of the Tube Amp Book
    (or Vols. 1 and 2 for that matter!) so there's no problem there.
    
    re: .550
    >Well, Dom, Jay used to make offers like, "I'm cleaning out my files;
    >send me a SASE and I'll send you a bunch of vintage literature."  So I
    >did once, to that address, and never heard from him.  I don't know what
    >that means; however, my letter did not come back "Addressee Unknown".
    
    Hmm, sounds a bit strange. Maybe it was just a problem with the postal
    service - after all, I can't see what would have been in it for him
    (unless he collected SASEs!). Actually, that represents a problem for
    me; I'm writing from Italy, so an SASE wouldn't be a lot of use to him.
    I'd have to send some sort of international post coupon to pay the
    delivery cost from his end.
    
    The main reason why I wanted to contact him is because I've done the
    rounds of the flea markets/antique shops here in Milan (of which there
    are very few) and there is *nothing* in the way of old tube amps. I get
    the impression that only Voxes found their way to Italy back in the
    60s, and of course they cost the earth.
    
    I could wait until I'm next back in the UK (the want ads/pawn
    shops/markets are flooded with vintage gear there). But it's always a
    bit difficult buying secondhand when you're a non-resident (i.e. you
    usually have to wait a while for the right bargain). 
    
    So I wanted to know Jay's opinion of Davoli amplifiers. Apparently, the
    Beatles and the Animals both used them when they toured Italy, and I do
    occasionally see them kicking around. I'm sure Jay would know something
    because I remember one of the questions in his tube amplifier quiz
    (that never got answered!) was to name two tube amps made in Italy.
    
    Dom
    
    
    for

    I've seen pics of Davoli amps, and I know they also made keyboards, but
    have no idea how good they were.  Considering that most pics of big
    rock bands touring Europe show stages full of UK-made amps, my guess
    is Davoli isn't anything too hot, but the answer is always listening to
    the amp and deciding for yourself.
    
    Awhile ago, I entered some replies about how US and UK amps are
    everywhere, some German brands have popped up here and there, but
    except for a few Roland and Yamaha amps, the Japanese and Europeans
    have never had a high profile in the *US* amp market.  What *do* the
    gigging club musicians use in your neck of the woods?
    
    							Brian

     Dom,

     Have you ever seen or heard of STEELPHON amps? I acquired
     a STEELPHON Pioneer last year and it seems to be a European
     brand. It has a multi-voltage selector on the front panel,
     similar to a VOX, and alot of the parts have Ducati printed
     on them. It may be an Italian brand.

     Neal

    re: .552

    >Awhile ago, I entered some replies about how US and UK amps are
    >everywhere, some German brands have popped up here and there, but
    >except for a few Roland and Yamaha amps, the Japanese and Europeans
    >have never had a high profile in the *US* amp market.  What *do* the
    >gigging club musicians use in your neck of the woods?

After 552 replies, I hope people won't begrudge us deviating slightly from the
base note...

To answer your question, I guess it's fair to say that you rarely see anything
"out of the ordinary" in Italy re. musical gear (I can't speak for the rest of
Continental Europe, though). You've got to realise that the whole
infrastructure here doesn't bear comparison with the UK or the US. I used to
hear people complain that to get time on national TV/radio, you had to play
traditional Italian waltz music, and the club scene was pretty much the same
story! Sure, that's changed now, but you get the drift.

So you'll see your Fender, Marshall, Peavey, Yamaha gear and so on...most of
the big names have got distribution deals here. What you *don't* get are the
quaint little things from the past...Mosrite, old Fender Broadcasters, Orange, 
Ampeg. As for rare valve gear in pawn shops, forget it. Two of the other guys
in my band are vintage nutcases, but they went to London to get most of their
gear. The bass player's got an old Hofner bass and a Fender Coronado; the
guitarist has just bought a '64 Les Paul. They've also got an AC30, a Farfisa
organ and a Leslie cabinet between them. But they're real enthusiasts - their
record collections are full of Paul Revere & the Raiders, the Hollies, the
Kinks, etc., all on original vinyl purchased in the UK at hefty prices.

For practicing, we tend to book two-hour sessions in local practice rooms, 
rather than renting a place; this actually works out cheaper. The
amplification, mixers, PA, drums are included in the cost (about $15-18 for 2
hours, not a lot if there are 5 of you). The amps are usually Laney, Marshall,
Fender, Hughes & Kettner, Peavey, Roland...but *always* solid state stuff.
Obviously, having people blow valves (through not warming up the amp) would
increase their costs no end.

Dom

    
    re: .553
    >Have you ever seen or heard of STEELPHON amps? I acquired
    >a STEELPHON Pioneer last year and it seems to be a European
    >brand. It has a multi-voltage selector on the front panel,
    >similar to a VOX, and alot of the parts have Ducati printed
    >on them. It may be an Italian brand.
    
    Can't say I've heard of STEELPHON, Neal, but they may well be Italian
    (I do recall hearing about another brand that had Ducati parts).
    Actually, I do sometimes read ads. here, for brands I've never heard
    of, but more often than I get the impression that they're hi-fi amps that 
    have been advertised in the wrong section of the newspaper! 
    
    It's a pity that there seems to be little or no old/vintage stuff to be
    found here, because the Italian mindset (gross generalization coming
    up!) is very much geared towards "the newer, the better" (Ostentacious?
    Never!). There aren't too many secondhand shops of any sort, and people
    seem to think that it's no good owning last year's Ferrari because it's
    already been rendered obsolete. In short, most of my musician friends
    can't fathom out why I'd be interested in old valve amps anyway!
    
    Dom
    

    You must teach them the way, brother Dom.

    --Brother Ron McDuff

    Dom,
    
    Here in the US tube amps that don't say Fender, Vox, Ampeg or Marshall
    on them also aren't of much interest.  You can still pick up brands
    like Sunn, Supro, Danelectro, Silvertone, Traynor, etc. dirt cheap, but
    they are not as easy to find as they were even ten years ago.   The age
    of these amps is leading to greater scarcity, most of the used amps I
    see around are solid-state, simply because that's what most companies
    have been cranking out for the last twenty years (if an amp can last
    twenty years, it'll probably last forever!!).  
    
    Some of these are great amps; heck for $25, it doesn't have to be as
    great as it would for $2500  8^)  8^)  
    
    Besides, Italy has a bad record with riots at rock shows...I suspect
    all of the old amps get trashed by irate audiences  8^)  8^)
    
    							Brian

        re: .556, .557

    Actually, it wasn't my intention to blast the Italian music scene.
    Things have come on leaps and bounds in recent years, although lots of
    gigs seem to get mysteriously cancelled at the last moment these days 
    (probably due to the recession - poor ticket sales). More and more
    people seem to want to form bands (which can't be a bad thing) and
    the prices charged for gear aren't much above those in the UK, although
    this is probably due to the fact that the lira is currently going
    through a bad time.

    The point I was trying to make is that "secondhand" is almost a dirty
    word here. The secondhand book and record shops can almost be counted on
    one hand: what hope of finding valve amplifiers made 30 years ago and
    (possibly) never imported, with the exception of Voxes, Fenders and one
    or two of the other "majors"?

    Sure, I'm well aware that 90% of the population of the UK/US aren't
    interested in these items either. But at least there's some sort of
    market, and you know it's worthwhile combing pawn shops, flea markets,
    etc. The problem here is the lack of flea markets! Oh well, next time I
    go back to the UK, I'll try to keep my luggage light ;-)

    >Besides, Italy has a bad record with riots at rock shows...I suspect
    >all of the old amps get trashed by irate audiences  8^)  8^)

    Amazed this news got out to the States. To be fair, I think it dates
    back to a period of political unrest at the beginning of the 70s. The
    most notable incident was a Santana concert when a Molotov cocktail was
    thrown on stage and burned down most of Carlos's PA! They
    understandably refused to play in Italy for the next 10 odd years.
    I've never seen any trouble here myself (unlike back in Britain...).
    The biggest hassle is people telling you to "sit down" when it's an
    "all standing" gig (i.e. no seating provided). So the band comes on and
    the audience automatically sits down - great for morale!

    Hmm, enough ratholing for one note ;-)

    Dom 

    If ya wanna really cry, howzabout that German concert where the
    Jefferson Starship lost all their gear due to a riot...guitarist Craig
    Chaquico had a stack of five (!!!) beautiful white tolex Bassmans that
    was lost (there's a pick of this setup in Aspen Pittman's "10 Greatest
    Amps" article that ran in GP a few years ago).  No wonder he switched
    to Carvins  8^)
    
    Then there was that UK Traffic show where Dave Mason had a couple of
    pre-war D45s get smashed...ouch!!
    
    						    Che Guavajelly

    Maybe we could latch this onto the Pete Townshend note? ;-)
    
    Dom

    re: .553
    
    >Have you ever seen or heard of STEELPHON amps? I acquired
    >a STEELPHON Pioneer last year and it seems to be a European
    >brand. It has a multi-voltage selector on the front panel,
    >similar to a VOX, and alot of the parts have Ducati printed
    >on them. It may be an Italian brand.
    
    Neal, By sheer coincidence (or maybe as a result of your having
    mentioned them in this conference!), this weekend I happened to chance
    upon adverts for TWO Steelphon amps in the Italian equivalent of the
    Want Ad. newspaper! So I think you can take it that they ARE Italian,
    although I've yet to find someone who knows anything about them
    (they're probably pretty old).
    
    So, what's your verdict on the Steelphon Pioneer that you found? Would
    you use it in a live situation or is it seriously lacking in some
    respect? Incidentally, the two amps I saw were priced at about 110,000
    lire - may seem a lot to you guys, but that translates to about $65,
    and you don't find anything for that sort of money here!
    
    Dom

     For awhile there I thought I had the last one in existence. 
     I got mine for $25 but $65 is still pretty cheap for a nifty
     old tube amp, regardless of it's make. Mine sounds alot like
     a Fender and has alot of the same features. It's about 50W
     and would have to be turned up pretty loud to distort, but I
     wouldn't hesitate to use it for a gig.

     Nealphon

    I picked up a new book over the weekend called "AMPS! The Other Half Of
    Rock and Roll" by Richie Fliegler.  It's published by Hal Leonard, $25.
    
    Richie is the product manager for Marshall and former NY session man. 
    His book is not as technically detailed as Aspen Pittman's book, but it
    does cover some different ground, solid state amps for one thing.  But
    I wouldn't call this a definitive reference by any means.  He gives
    some company histories, but many are pretty simplified (like Kustom)
    some are missing (nothing on Peavey, for instance) but there are
    interesting new additions to the Ampeg story plus poop on Sunn (hey, I
    didn't know the company was started by the bassist for the Kingsmen!). 
    Some cool pictures, including a Rick Transonic stack (so howcum no text
    on Rick amps?), some amps you already saw in Apsen's book, some nice
    Oranges, an Oliver with the motorized head, some early solid state
    Fenders (haven't seen any pics of these for many years), etc.
    
    There are some discussions of whether reissues live up to the originals
    (Richie says nope) and an interesting shootout of various versions of
    the Fender Pro amp.
    
    Overall, the book could have used some tighter editing but it's worth
    owning if you're curious about old amps and already have the Pittman
    book.
    
    							Brian

    Another thing Brian failed to mention, Ritchie's sense of humor. 
    Often the writing in these kinds of books leaves much to be desired,
    but Ritchie's style is bright and entertaining, plus his love and
    enthusiasm for these old beasts really comes through.  It's a great
    book to sit down with.
    
    Ritchie also recently started doing a tech column, for Guitar World
    I think.  Probably the only reason left to actually buy that mag.
    
    /aspmann
    

    I had heard that Sunn was started by the Kingsman bassist, but that's
    the sum total of what I know about that company. That probably
    explains why they made killer bass rigs with little else to offer.

    --Ron

    Actually, Fiegler's book claims that as late as 1970, Sunn was
    outselling Marshall in *guitar* amps.  The possible secret to Sunn's
    tube stuff is that the power stages were designed (and originally
    built) by Dynaco, who are still well respected for their tube hi-fi
    amps.
    
    Oh yeah, Fiegler, like me, wants to know where all the old amps went. 
    As he puts it, you'd think that four and a half foot tall appliances
    that cost over a thousand dollars wouldn't just vanish from the face of
    the earth without someone knowing about it.
    
    							Brian

    That's not all that surprising, I don't think that Marshall was doing
    very big numbers in the US in 1970. Not that the demand wasn't growing.
    But I think dealers were having a hard time getting them.

    And yeah, think of all the Fenders, Sunns, Traynors, etc that are hiding
    in musty places all over the country. That's enough to make you nuts.

    --rjb

    >And yeah, think of all the Fenders, Sunns, Traynors, etc that are
    >hiding in musty places all over the country. That's enough to make you
    >nuts.
    
    Well, there are no more Fenders hiding (at least without $1000+ price
    tags 8^)) and it's *playing* the Traynors that makes you nuts  8^)  8^)
    
    							Brian

>Well, there are no more Fenders hiding (at least without $1000+ price tags

    Ha ha, THAT'S what they WANT us to *THINK*! Ha ha ha ha ha ha ha...but
    they're really EVERYWHERE. These vintage dealers want us to think
    they're just clever but all they really do is hire guys to randomly
    break into houses and check the basements and attics. Yeah, I'm onto
    them.

    --rjb

   Here's an interesting posting from the alt.guitar.amps internet newsgroup.
It's a comparison of gain between many types of 12AX7 tubes; 12AX7s are used
in amplifier preamp stages, as a phase inverter, and as reverb or effects loop
buffer.

----------

Article 332 of alt.guitar.amps:
Newsgroups: alt.guitar.amps
From: [email protected] (Tom May)
Subject: Interesting 12AX7 gain test results.
Sender: [email protected]
Organization: The Planet Eden
Date: Sun, 26 Mar 1995 18:32:24 GMT

Hi,

I decided yesterday would be a good day to test the gain in all my 12AX7s.  I
used a circuit with a 1M grid resistor, 68k grid stopper, 2.7k cathode resistor
bypassed with 50uF, a 220k plate reistor (no other load), and a 340V power
supply.  My input signal was 200Hz 100mV p-p.  I only tested one half of each
tube, unfortunately.

Here is how they all stacked up, in descending order of gain:

Sovtek 12AX7WXT         78
Sovtek 12AX7WXT         76
Radio Shack 12AX7A      76	(German-made for Realistic )
Sovtek 12AX7WXT         72
Sovtek 12AX7WXT         72
Hungarian 12AX7         68
GE 12AX7                64
Hungarian 12AX7         64
Hungarian 12AX7         64
GE 12AX7                58
RCA 12AX7A              48

The Sovteks are new.

The Hungarian tubes were in my amp when I bought it in the late 80s and for
all I know had been in it since it was manufactured in 1980.  It looks like
the manufacturer is Tungsram, but the letters are all fairly rubbed out.

The RCA had been in my amp 2 years.  I don't know if it was NOS or just O when
it was installed.

The GEs and Realistic are in an amp I've had since about 1982.  The Realistic
was in a channel which hasn't been used since at least 1982.

So I take back what I said about the Sovteks not having more gain than the
Hungarians (I said that somewhere).  Also, either the American tubes were not
that great to begin with or they haven't aged well.

Tom

As a point of refernece I bought a shitload of 12AX7WB's from Sovtek last fall
(along with a bunch of EL34's, 5881's etc) and replaced all my preamp tubes
in all my preamps (two kitties, a triaxis, semour duncan and the rivera) and I 
really like them. these are great tubes and for me there's the little caveat
of helping some workers in the former "evil empire" convert to a peacetime
economy. Besides the boxes they come in look cool with the hammer and cycle
and all...

You can order directly from Sovtek AKA New Sensor in New York provided you have
the minimum order ($50 I think), just be prepared to BS a little, my order was
big enough and I maskeraded as a repair guy. You do need a copy of the latest 
price list, I subscribed to Glass Audio (the tube bigot mag for golden ears
stereo types) which always has New Sensor's latest prices on the back.

Andy just had his old blackface vibro redone (with some of those tubes) and it
really sounds nice, a full retube and rebias done by none other than Grievie
King (who sends his regards to all). 

dbii

    Does Groove Tubes still make that catalog with all the trick amp mods
    in it. It's refered to quite a bit in the earlier entries of this
    conference. I'm thinking EL34's in my Silverface Bassman....
    
    -kev

    Groove Tubes does have a book of mods called "The Tube Amp Book",
    but I don't recall seeing a mod for making a Fender into a
    Marshall...
    
    :-)

    Sure, it's called trade-in :-)
    
    Actually, that book may have what you're looking for.  I thought they
    did in fact have a Fender ==> EL-34 conversion in there
    
    I'll try to remember to check tonight
    

I thought I put this in here somewhere.....

			Changing 6L6's to EL34's


Between pins 4 and 6 on each output socket is a 470 ohm resistor replace that
with a 1000 ohm 5 watt resistor.

Between pins 1 and 5 on each output socket is a 1500 ohm resistor,disconnect 
it from pin 1,and solder it so that one end remains on pin 5 and the other end
stands straight up. Connect the wires that ran to pin 1 to the ends of the 
1500 ohm resitors that are standing free.

Connect pin 1 to pin 8 with solid wire.

Rebias the power tubes.....
    
    I've tried this on a couple of amp's,it works....
    

    Many thanks. Now i've got to find the time to do this.
    You mentioned doing this a few times.How did it effect your overall
    tone? (i hope that's not a stupid question). I want the bottom from a
    Fender and that Glassy high end from a marshall...with out the
    marshall.I figured the EL34 swap might be the answer,may be not but
    it's got to be worth a try right.Besides,one must tinker,or not exist.
    
    -kev_in_pursuit_of_THE_tone-

    Wear rubber gloves when you do this, so you'll be around long enough
    to enjoy the subtle tonal variations from this mod.
    
    Mark
    

    
        I have a straight tube amp that is about ~30 years old. I found
    only 3 of the tubes that go into it. 2 are 6l6's and the rectifier tube
    is a 555. But what goes in the other 3 slots? There are no markings and
    the name-plate that was rivited on the back is gone too....bites!
        Also, I have a thing of the same vintage called a "Generation
    Booster" thats about 1.75" square and 7" long with a standard .25" male
    phone jack on it. What is this thing?  BTW...I'm new here.
    
    -john