Conference napalm::guitar

    There are a few notes in here already about tube replacement.
    Do a DIR/TITLE="tube"
    That should lead you to these notes.
    
    Good luck
    Mark

	A friend of mine was just in Tewksbury Music Center.
	(1269 Main st. RT. 38) He said that they have fender tubes.
	Also said that they were quite cheap. Said the folks were
	generally real helpful (not specifically on tubes).
	You might give then a try, since they are in the neighborhood.

	Let us know how you do.

Rick

    
    	I saw a pair of 6L6's, Peavey ones, at the Acton Music center,
    for $25.
    
    	Joe Jas
    

    
    
    	I have a question about which tubes to buy.
    
    	I say an ad in guitar player for Mesa Boogie Matched tubes.
    	I also saw an ad for Groove Tubes.
    
    	I understand that matched is the way to go,but should I 
    	buy the boogie tubes ($71.00 complete) or grooves tubes
    	($??.??).Are groove tubes more expensive than mesa tubes?
    
    	Alternately,should I save some bucks and buy whichever tubes
    	I can find.
    
    TomG

    Are you just looking for a set of good durable matched tubes,or are you
    looking to alter the sound of your amp by using soft or hard tubes.
    Mesa offers only one version of a 6l6GC power tube. Groove tubes offer
    10 differant ratings ranging from #1 soft to #10 hard. A quartet
    of Groove tubes will run you $80.oo. 
    
    By the way, neither company makes tubes. They buy them and test
    them to their own tight specs, or they have the manufacturer test 
    them. I'm am not sure if they get them from Sylvania, GE, or someone
    else, but they must conform to their specs either way.
    
    Fender tubes are supposedly "special design" but I doubt if there
    is much about them that is special. They are not matched, and I
    would imagine they are tested to a rather loose spec. I bought a
    new Fender Twin in January, and had to change power tubes a few
    weeks ago, because the original ones were getting microphonic on
    me. I am not usually this hard on tubes, but the new Twin has a
    high-gain stage, which probably eats tubes faster then the older
    Fender amps ever did.
    
    I changed all the tubes in my silver faced twin about a year ago,
    including the preamp, reverb, tremelo, and phase invertor tubes,
    and power tubes. The total cost was $175.oo. I have heard that
    the groove tube preamp tubes are not really worth paying more for
    because they are not matched, or tested to any special spec. They
    cost about $12.oo each if they helps at all. 
    
    I did not notice a huge differance in the sound of my silver face
    twin after spending this much money. I did need new tubes badly,
    but I could easily have made due with a less expensive set of tubes.
    I guess what I'm gettin at is that for most purposes the Mesa Tubes
    are probably the best buy.
    
    Whatever you decide, good luck.
    
    Mark 

    Matched tubes are not that important and can be balanced for
    if this is your desire. The tubes you will get from the electronic
    supply house are the same tubes at 1/3 the bucks.
    
    Jim
    

    MY local electronic supply house charges MORE than Mesa does for
    tubes.  Not much demand for them, therefore the price is high. 
    Example:  12AX7 from Mesa was $8, from my local electronic supply
    was $14.
    
    Greg

Newsgroups: rec.music.makers
Path: decwrl!labrea!csli!crimmins
Subject: Tube Amps and Groove Tubes
Posted: 19 Sep 88 17:38:12 GMT
Organization: Center for the Study of Language and Information, Stanford U.
 
 
I received the following reply via e-mail to my query about tubes and
tube amps.  I didn't see it in the newsgroup, so I forward it here
because it is so informative, and I'm sure there are others who'd be
interested. 
------------------
 
From: rich%[email protected] (Taste Takes A Holiday)
Message-Id: <[email protected]>
To: [email protected]
Subject: Re:  Tube questions
 
When your Fender amp distorts at abnormally low levels, it will
generally be a power (6L6) tube that has gone bad.  Those other noisy
little gremlins that get into the amp occasionally may be either
pre-amp or power amp tubes.  If its sort of a 'frying eggs' sound
its generally a power tube, a ringing sound is generally a pre-amp
tube.
 
As far as buying tubes locally, check Associated Radio (on Middlefield)
in Mountain View.   They have an excellent stock of RCA tubes.
 
On the Groove Tubes, paying $30 a tube is a bunch of shit.  All
they do is test them, and package them into like sets.  Buy your
tubes from Boogie, they have all the tubes you need for your Fender,
and they're a lot cheaper than Groove Tubes.  I tried Groove Tubes
in my Boogie, they just aren't quiet enough and drove me nuts.
You can get a 6L6GC for $18, a 12AT7 for $11 and a 12AX7 for $8.
(That covers all the tubes in your Fender if I remember correctly,
its been a long time since I fixed one.)  On the tube chart where
it specifies 7025s rather than 12AX7s (7025 and 12AX7 tubes are
interchangable, the 7025 is a little quieter) use the Boogie SPAX7,
which will set you back $16.50 each.  The SPAX7 is even better than
a 7025.
 
As far as the tube tester goes, it will spot a DEAD tube, but forget
about trying to find a noisy one.  This you have to do by swapping out
the tubes one at a time.  You can make a preliminary test by removing
the can that covers the tube and tapping the tube gently with the eraser
end of a pencil while the amp is on.  Many times a noisy or ringing
tube will show itself very plainly when tapped on.  You will hear
the tapping in the speakers on ALL the tubes, look for the one tube
that makes an abnormal sound when you hit it.  Another rule of thumb
is that in a Fender, signal flow is from the tube on the far left
(looking at the amp from the back), down to the power tubes on the
right.  Tubes which are bad will create more severe symptoms when
they are in the far left sockets.  This is because there are more
stages of gain following them to amplify their defects.
 
Again, I think the best tubes come from Boogie.  You can order tubes
from them 24 hrs. at (707) 778-TUBE.  (that's in Petaluma, Ca.)
I give them my credit card number, and I get my tubes UPS in about
3 or 4 days.
 
Standard disclaimer:  Even though my system is named boogie, I have
no connection with Mesa/Boogie except as a very satisfied customer.
 
 
 
Regards,
Rich
 
 
----------
 
Rich Koch @ Sun Microsystems, Mountain View, CA
{ihnp4|seismo|decvax|ucbvax|hplabs|amdahl}!sun!boogie!rich	(UUCP)
[email protected]	(ARPA)
    

    I have just purchased a Watkins Dominator valve amp for 10 pounds (yes I
    suppose you could say I was given it, for the price!). 
    
    It is in pretty good nick for age but it needs cleaning up
    (electricly). It has quite a lot of hums, crackles, and hissssses. I
    don't know what the state of the valves are as I know *nothing* at all
    about valve amps (or amps in gen. for that matter!).
    
    I would appreciate if some more enlightened person than myself could
    give me some info on what to do. 
    
    Should I take it to a repairers of some sort?   If so Where?
    
    Could I do something myself?   If so What?
    
    Anything at all would be greatfully received and might save another
    oldy from going down the drain......
    
    Cheers,
    
    Arfon.  ( U.K. Reading.)
    
    
    
    

    If you don't know much (anything) about tube/valve (U.K.) amps,
    then don't mess with it.  I mean you could replace the valves your-
    self and clean it up cosmetically, but don't go messing with any
    of the electronics.  The reason is that valve amps hold some very
    high voltages (Neal, and others, can clarify this) even when they're
    not plugged in.
    
    My vote = take it to a qualified repair person.
    
    joe.

    see my entry in note# 396.18 for info on Groove Tubes and their
    book on tube amplifiers.
    
    You can also order groove tubes (atleast EL34's and 12AX7's) from
    CARVIN (a current manufacturer of tube amps) A set of two EL34's
    runs $35 and a set of four $69; 12AX7's are $8 each)
    
    CARVIN can be reached: 1-800-854-2235

	's anybody know where I can get some TUBES?

    I'm sure there are many places.  I saw a posting yesterday saying that
    Carvin was selling Groove Tubes for pretty good prices. 
    Stewart-MacDonalds has their own line of tubes now and the prices seem
    good.  Let me know what you're looking for and I'll post their prices
    for 'em.
    
    Greg

    Stewart-MacDonald is now selling Ruby tubes.  I recently ordered a
    bunch, but haven't installed them yet.  They have 12AX7 and 12AT7s
    with a quantity discount on 6 or more.  Power tubes offered include
    6L6s, 6V6s, and EL34s.  Preamp tubes are $6 to $8 depending on type 
    and quantity.  A pair matched of 6V6s is $18 (quantity of 3).  In 
    comparison, I had a music store quote me $40 for a set of Peavey 6V6s.
    
    The tubes that I got were made in the USSR.  
    
    Jim

	I was being a wise a$$ and got what I deserved.... 

    	Hey! You should he able to find the TUBES in most of your favorite
    record shops, great band and a lot of the guitar is Steve Lukather!!!
    
    	FJE
    

    >It's time to replace the tubes in my JCM900.  Question is, I don't
    >have any documentation, and I'm wondering what type of tubes the
    >small ones are.
    
    For Marshalls, typically they use 12ax7 preamp tubes.
    
    
    >It's a 100 watt combo model, and has 4 El34's along with the 3 smaller
    >ones. Also, which are actually the preamp tubes (yeah, stupid question
    >I know), I think it's the EL34's, but I'm not actually certain. 
    
    The 4 EL34 tubes are the OUTPUT tubes.  The three, smaller (in grey
    metal socket caps) are your preamp tubes.
    
    
    >Any recommendations for the replacements ?
    
    When I retubed my Marshall, I went with the Marshall EL34 replacement 
    tubes for the output stage and Grrove Tubes 12ax7's for the preamp
    stage.  Sounded mint to me.
    

   If you change the output tubes, puchase them in either "Matched Pairs"
or "Matched Quad". Quad's for the four-tube unit. As Buck said, the preamp
tubes (small ones) are generally 12AX7's. You may find different numbers
like 12AX7/ECC83, ECC83, 12AX7A, 7025's. All are suitable for the general
guitar player. The most common are 12AX7/ECC83's & EL34's.
   If you replace the output tubes, have the bias checked by someone qualified
or someone you trust. It shouldn't take long.


/J 

     Thanks for the info guys.  I belive the 12ax7's are ECC83's, there
     is a number printed on them in red, but it was fairly difficult to
     read.  I'll be seeking them out today.

     Regards, Larry
   

    ECC83 := 12AX7
    
    

>    ECC83 := 12AX7
    

$! Addendum... 
$!
$  ECC83 := European version of the 12AX7!   - Or -
$  12AX7 := American version of the ECC83!   Which one was the chicken though...


*8^))

    Yeah, and the 7025 is...someones version of the 12AX7 and the ECC83...

       Yowser, this is an expensive proposition as I'm finding out.
       How important is it for me to have the amp rebiased once the 
       tubes have been replaced ?  Is it necessary that I have a
       schematic diagram of the amp ?  I tried getting one from the
       company before with absolutely zilch luck.  They basically
       sent me mail telling me a schematic wasn't available.  This 
       was Marshalls US representative (Korg I believe).  I need the
       amp real quick for some impending gigs this week and can't
       really have it tied up in a store/repair shop.

       Thanks, Larry

    	How lucky do you feel? And how much money do you have to burn?
    
    							Rick
    

    Chances of worn toobs becoming catastrophic are pretty unlikely.
    Mostly, you might get some noise, and/or lack of volume.
    
    How important is the bias check?  Well, it depends on how long you
    want to wait until you need to lay out the dough for another
    quartet of bottles.  :-)
    
    Should take a competent tech (aoxymoron?) about 15 minutes to check
    your bias.  A while you wait thing, perhaps??
    
    You could slap the new toobs in, play your gigs and have the bias
    checked next week...??

         Finding replacement tubes can be a major pain in the *ss.
	 Not many stores seem to stock them, or have more than a 
         couple in stock.  The prices for GrooveTubes were ridiculous
	 imo, and the only place I could find that had Marshall EL34's
	 was in Tewksbury, he wanted 118$ for the 4 EL34's and 3 12AX7's.
	
	 Anyways, I ended up with 4 TESLA EL34's and 3 SOVTEK 12AX7's
         from MACDUFF's for a grand total of $70.  One of our own is 
         going to check out the bias this week for me so all should be 
         well.  Had I more time to shop for a deal and not have to special
         order, I would have considered other brands.  Unfortunately, I 
         need them now (basically, my amp crapped out over the weekend,
         nothing major, just lack of volume & punch, and one of the tube
         failure LEDS lit-up.)  I have a busy week of practice for a gig
	 I'm involved with Friday night and I gotta have my amp.  

	 Thanks for all your help - Larry

    Re: high tube prices
    
    You think GT is high?  Check out this from a 1993 Ampeg price list
    (these are factory retail, OK?).
    
    6550 USA G.E. Power tubes, tested, matched and graded.
    
    $100 per pair (choke).
    
    Set of six (for an SVT) $300 (gag).
    
    						Aspen Pitbull

    Really - $100 will buy you a damn nice MIDI card!!
    :-)
    
    FWIW - I've always thought GT's comments about soft/hard and matching
    were a load of sh*t anyway.
    
    "Lesse - this EL34 is crapped out totally...  Hmmm, so isn't this
     one!!"  (Insert technician pulling out a pen and writing "S-2" on 
     the tubes)
    
    Sha!

    Hey Larry, you never really said - why is that you feel you have to
    retube anyway?  Are you having some problems with the current ones?
    Is there a recommended replacement schedule in the manual or something?
    Just feel they've been in there too long?
    
    I can see replacing the output tubes on a regular basis as preventative
    maintenance, but preamp tubes don't need replacing nearly as often if
    ever.  Conventional wisdom with preamp tubes is if they ain't broke
    don't fix em; I'd recommend holding off on those and saving yourself
    some bucks.
    
    /rick

           Hi Rick,

            Well, I've had the amp for several years now, and I hadn't
	   retubed at all.  I have been noticing a decline in performance
           for awhile now, and suspected tubes but have been putting it
           off due to the cost factor.  I just figured since I was doing
	   it, I might as well do them all.  Biggest changes were a lack
           of punch and a loss of brightness (life) to the sound.  It sure
           wasn't sounding like what you'd expect at a moderate volume 
           level.   This weekend I switched it over to 100 watt mode vs 
           the 50 watt mode I normally use, and zip, less volume than in
           50 watt mode, and the tube failure LED lights up.  

           The good news is that the gig Friday night more than covers the
           cost of the tubes, and still allows me to buy the CD player
           I've wanted for a long time.  

           Larry

You sure the amp isn't just making you deaf? Just kidding. (sort of).

    --Ron