Conference napalm::guitar

    
    The following is a plea for leads toward a wah-wah
    schematic,(preferably the original Cry-Baby schematics, but I'll take 
    whatever I can get..)
    I have edited out some of the original message, but the basic request
    is intact.                                        
                                                      
    Hope this conference proves a little more fruitful....
    
    /doug
    ===================================================================
    
The bottom line is this:  I recently inherited a non-functioning Cry Baby 
Wah Wah Pedal from a guitarist friend of mine.  My pride became somewhat
wounded when I couldn't troubleshoot the problem *without* schematics.  I 
think some of the components literally have ROTTED internally (road use can
be hard on old pedals).

I need one of two things: 
        1. A genuine schematic to a Cry Baby Wah pedal so I can fix this one
   or
        2. A plain-vanilla schematic of generic wah wah pedal so I can rip
           the guts out of this one and build a new one.

Now I've done some looking for wah schematics and just general variable
filter-type circuits and the ones I could find all used some off-the-wall
voltage supplies. For ease of use and compatibility, I want a simple 9
volt dc power supply. I really don't have the time/inclination to try to 2nd 
guess & redesign someone else's ckt. to a single 9vdc power supply.

I can be reached at NUHAVN::MCPHERSON
My LOC/MS is        APO-2/C8
                    DTN 289-1939

Any help will be appreciated.
                                   

                                    Thanks,
                                    Doug
                                                          

    Are you looking for anything in particular? Or are you starting
    a reference library?
    
    Edd who_has_the_prints_to_his_Ampeg_B25B_Bass_Amp
    

    	
    Nothing in particular and yes,the beginning of a reference library.
    
    

    I, too, am interested in schematics.  In particular, does anyone
    out there have a source for the schematics to a Fender Deluxe Reverb
    and a Princeton Reverb?  
    
    Thanks in advance,
    Johnny Jupiter
    

    I am interested in the schematics for the Fender Bandmaster. In
    ref to .3 I have a friend who has a Princeton Reverb. I will ask
    him to see is he has the schematics for it.
    

    I have the schematics for a Deluxe Reverb (approximately 1963 vintage).
    I can copy them for you if that's what your looking for.

    Thanks to you pickers and grinners out there who helped me locate
    schematics...I've already started tearing my Princeton Reverb apart!
    
    Are there any EE's out there who could explain to me how to convert
    an 'old style' two-prong AC plug to a three-prong configuration?
    Is it as simple as running an additional (green?) wire down the
    line cord and tying it to the chassis somewhere, or do two- and
    three-prong AC systems differ in a more fundamental way? 
    
    Again, thanks for your efforts on my behalf.
    
    Regards,
    Johnny Jupiter
    

>    Is it as simple as running an additional (green?) wire down the
>    line cord and tying it to the chassis somewhere, or do two- and
>    three-prong AC systems differ in a more fundamental way? 
    
Maybe, maybe not......
In theory, that third prong does ground the chassis, but that function
may already be present in your device if the two prong plug was polarized.
"Polarized" means that the plug will only go into a socket one way.
Is one of the two prongs wider than the other?
If such is  the case, the chassis may already be grounded.
Cheap TVs are often  built that way.  The plug has to be polarized,
because if it weren't, you could plug the chassis into the hot side
of the line.  The equipment would work fine, but if you touched the unit
and (say) a radiator or faucet or other grounded item at the same time, 
you'd get fried.  If you added a ground wire to the chassis and
didn't obey the polarization, you'd be shorting power to earth, killing it.
The technique is cheap because it saves an isolation
transformer.  Most audio equipment is not built this way, however,
so you might be okay.
But why bother?

- tom]    

    Re .7: Here's the reason for my request...the AC situation in clubs
    is so incredibly lame that it's possible to get all the band's
    equipment at the minimum buzz level (and I HATE guitar amps buzzing!)
    and then have a healthy voltage between the guitar and a microphone
    stand.  Alternatively, one can flip the plug upside down to minimize
    the buzz (many amps have a polarity switch...I'm pretty certain
    it just swaps the input to the power transformer) for safety's sake,
    only to have a serious buzz show up everywhere.  We try to minimize
    stuff like this by running the entire band off one leg of the main
    breaker, but it's still a "get there and see what works" approach.
    
    It seems my newer amps, all featuring three-wire AC cords, are
    substantially quieter than my favorite, the Deluxe Reverb.  It's
    not clear to me if this is a result of inherently better designs,
    or if the three-wire system contributes to noise suppression.
    
    Maybe I could wear some dishwashing gloves while I play ;^).  Yeah,
    that's the ticket...I've always wanted a clean sound.
    
    Regards,
    Johnny Jupiter
    

    
    
    Don't know if this is possible, but.....
    
    Well, I've moved.  Unfortunately, apartment living now restricts
    me from cranking up my Boogie to ear shattering volumes.  In fact,
    I can't even turn it up loud enough to mic it without getting
    complaints when I'm recording.  (I usually do most of my recording
    later in the evening anyway, so...)
    
    What I'd like to know from any EE's out there, is there a way of
    building a 'line out' (whether its actually inside the amp or
    outside the chasis doesn't matter to me) so that I can run
    directly to my board?  
    
    I don't want to have to get a rockman or whatever to record with,
    as 1. I can't afford it right now, and 2. I hate the sound of the
    Rockman.
    
    Is it possible to do what I'm asking without ripping my amp
    to pieces or paying an arm and a leg to have it done?
    
    Thanx,
    Ralph
    
    

    	What kind of Boogie? ie. MKI,MKII or SOBoogie etc. The Mark
    IIB has a preamp out right after the EQ circuitry. You essentially
    are looking at some wire and an output jack of your choice.
    
    						Rick

    
    
    re .10  
    
    Its an S.O.B.   Any idea if this has the same pre out?
    
    Ralph
    

    On the Mark IIB the preamp out is called "Slave" and there's even
    a handy level control.   Don't know if the SOB's or Calibre series
    has this but I'd be surprised if they didn't.
    
    I've made some experiments going direct into the board from the
    slave out.  Let's put it this way, I have a modest 4-track recorder
    and fairly junky mics, and my conclusion is that while recording
    this way is a compromise it's quite adequate if all you're looking
    to do is just put your ideas together.
    
    	db

    
    
    The SOB doesn't have a slave out.  However, it does have a feature
    called 'limit' that allows you to get some pretty low signals 
    while cranking the preamps and master volume.  I've tried running
    the speaker output into the board with the limit all the way up.
    The sound is better than anything I've tried with a mic, but
    I'm afraid of what I might be doing to the board or the amp.
    
    There doesn't seem to be any clipping through the board, so I don't
    think I'm pushing it too hard, but I could be totally wrong.
    Any opinions?
    
    Thanx,
    Ralph
    

	Wiring a preamp out should be fairly easy if you have a soldering
gun and a schematic. But you may want to have someone else do it for 
you who is use to doing it. It should cost you less than $40 if you go
by the rates I have heard of lately of $36 an hour and parts. If that
is alot of money to you right now then your alternative is to wait or do
it yourself which I have found to be neccesary as my budget can not afford
it either.
	A preamp out would disable your presence control on a Mark IIb however
if you don't have a the slave out which the Mark IIb has it is also possible to 
wire this in and would give you more control and less chance's of overdriving 
your mixer and is also simpler to wire.If you have a schematic of your SOB?
	It would be easier if I knew what the difference is control-wise and
tube-wise between the SOB and MarkII. Anyone want to try a comparision?


							Rick

	I have an old FOXX wa-wa/fuzz that is beyond repair. However,
    	I'd like to take the pedal, switch and the pot and make it into
    	a volume pedal. If I hook it up as shown below, will it work?
    
    
                                pot
                         ___/\/\/\/\/\/\/\___
    -----   signal       |end of  |                            ------
         -----+          |coil    |wiper                +------
    ----+     |     -----+        +---------------------+      +-----
        |     +----  <- in/out switch                   |      |
        |           ------------------------------------+      |
        +------------------------------------------------------+
    				shield

    A friend of mine used to own onw which I fixed for him...
    
    As I recall, it WAS a volume pedal as well...You pushed the pedal
    forward and hit a switch under the toe,,,
    
    Check to see if you have one,,,,most volume pedals have a battery,
    too, though I never took one apart to see what it was for.... 

    It MIGHT work.  The pot in it might not be a good spec for dropping
    the volume signal.  But give it a try.  I think the pedal will work
    the wrong way -ie you press down and the volume decreases, not
    increases.
    
    rep -.1  The volume pedals that have a battery in them have preamps,
    which is a good idea anyway if you are going to vary signal strength.
    

       The old type volume pedals did not have a battery and you really
    don't need one. If you don't filter the built-in pre-amp properly
    you will get noise. Take the exsisting pedal you have and use the
    exsisting pot, (hopefully 500k ) and run the hot wire to the center
    tap on the pot,from the input. Then, depending on how the pedal 
    activates the pot, wire the other hot (going to the output) on the 
    other side of the wiper. Wire the gnd wire straight through from the 
    input side to the output. You only need to actuate one of the two wires.
    Remember, a volume pedal is just a volume control for the foot, (so it 
    has something else to do besides tap on the floor). Also !!! Use shielded
    2 conductor cable. It will help to keep excessive noise down to
    the mimimum. Plain and simple. It is sometimes wise to keep it that
    way.                                                                
    
    Good luck !
    
    Fred
    
    P.S. Mine uses a photo-cell to increase and decrease volume, but
         that's another story.

    I use a volume pedal when playing pedal steel and guitar.  Initially,
    I used a pedal with a 250K audio taper pot in it, wired like the
    schematic in .0, but the pots deteriorated with constant use and
    quickly developed a healthy noise output.  Ernie Ball markets a
    pot based pedal featuring 'quick-change' pots.
    
    Subsequently, I acquired a Morley volume pedal which uses an
    opto-isolator to eliminate noise.  Works like this:  The AC signal
    arriving from the guitar modulates the output of a photo-diode,
    so the brightness of the diode varies in proportion to the signal.
    Contained in the same light-tight package as the photo-diode is
    another photo-sensitive device that produces voltage in proportion
    to the incoming light.  You play...the diode gets brighter...the
    receiver sees more photons and cranks out more volts...the volume
    goes up.
    
    The overall sensitivity of the emitter-receiver system is controlled
    a voltage that is modulated by the potentiometer connected to the
    foot pedal.  The important difference is the signal does not travel
    through the noise-sensitive pot; only a control voltage.
    
    And it works!  The Morley's incredibly quiet.  As an aside, I think
    a volume pedal is about the most under-rated effect ever.
    
    Regards,
    Johnny Jupiter
    

FWIW,

In the April 1984 Guitar Player, page 96, there is a schematic
for an opto-isolated volume pedal circuit.  Craig Anderton claims
it is a $10 circuit.  It might be worth a look - it should be
better than using a potentiometer directly.

						T

    I have a Marshall related question.  I have a 100W mosfet (solid
    state) head and just can't seem to get a good tone out of it.  Some
    buddies of mine say that there are some internal pots that can be
    adjusted for gain and tone.  Does anyone out there know for sure
    if these pots do exist before I go diving into the guts of my head?
    BTW, it's a 1986 head.
    
    					Jerry

    I have a Peavey Mark III bass head that just got toasted!!  Does
    anyone happen to have a schematic for this model that I could possibly
    get a copy of?  I'm going to try to fix it myself.
    
    Please reply by mail.
    
    Thanks,
    
    -Ralph- 

    
    
    Hi Everyone!
    
    Would anyone out there happen to have a copy of the scematics 
    for a DOD Performer Delay (585-A) stomp box?  I had to open one
    up in order to replace a pot and I noticed that there are two smaller
    pots inside.  I am wondering if these internal pots can be adjusted
    to increase/decrease the factory delay settings.  I am not about
    to try it at the expence of the pedal.
    
    Thanks!!
    
    chUck
    
    

If that's an analog delay that uses one of the SAD type delay chips don't
touch those pots! They adjust balance between the two channels (each channel
handles 1/2 of the signal) and the other pots adjusts out clock noise.

dbii

    Chances are, the pots inside are trims for the anolog circuitry.
    
    The capabilites of a digital delay depend on how much "memory"
    the pedal has. The more delay, the more memory is needed, and
    the more it costs, period. Memory chips come in lots of sizes,
    which determines how much data they can store. 
    
    Digital delays work as follows:
    
    signal from guitar = analog
    
    analog input ==> A to D converter ==> store in memory ==> wait n 
    milli-seconds ==> recall from memory ==> D to A convertor ==> analog output
    
    The input and output signals generally go through some sort of a
    preamp. Chances are, the pots control the gain of the preamps. Messing
    with them may cause noise, or cause something to blow, but it is very
    unlikely it will effect delay in any way.
     
	I would leave em alone.
    
    	Mark
    
    

Hi.

Does anyone have (or know where to get) schematics for a Tangent Series IV
console. Tangent is no longer in business and so far noone seems to
have schematics - and I've tried close to 30 repair shops!!

Thanks for the help.

Mark

    Are you sure about that?  Our church bought a 16 channel mixer from
    them 2 year ago, factory direct.  They have a factory here in Phoenix.
    
    I'll get the address for you and post it.
    
    Mike

    I'm posting the address in the Manufacturer's note.
    
    Mike

I need schematics for a Marshall 50wt JCM800 model 2205.
I'm selling it, and want my tech to put together a package
that shows the mods made to it.

Help !!

jc

Jay,

	Hi, I am interested in a schematic for a tube driver pedal. There are
one or two manufacturers and they are based on a 12AX7. Can you offer any 
help?

I can't find your location or DTN on ELF, can you print it in your next reply?

( I found a Jim but not a John or Jay !)

I am about to build another amp based on a MOSFET output module and op amp 
front end (based on the SESSION range).

Can you recomend a better schematic !  ( I am an analog design engineer but
with not a lot of experience on tube amps, and op amps are cheaper !)

Thanks in anticipation.

PS. Great topic, your enthusiasm is giving the NOTES file a new lease 
of life !!

Dave Litten  @SBP     DTN 782 2314   UK
 

    Hello folks:
    
    1st off, if you haven't found a schematic for the Vox wah wah, I can
    send you one, along with one for the rare Marshall Wah Wah.  These
    are from the orignal schematics, the Vox being a xerox, the Marshall
    was redrawn because the orignal copy I have is bad, the UK
    having bad fax machines.  Mail me a sase to the below address
    with a note of request.  The Marshall sheet has the rare Marshall
    'Ultra-fuzz' schematic also.
    
    2nd, I can be reached thru the name "TASHJIAN", this being my
    last name.
    
    3rd, everyone check out the 'TUBES..TUBES..TUBES' section
    for a future project on Tube pedals.
    
    Thanx for everything:
    
    Jay Tashjian
    

    OK, I gotta tell you, my first real amplifier was built from that same
    Sams Photofact schematic in 1965.  I really wanted an amplifier, but we
    didn't have the bucks.  My dad was in the TV business, so we got the
    Sams Photofact book, picked out the Twin Reverb, bought about $50 worth
    of parts (I seem to remember four 6L6s, but that could be wrong), and
    we made it.  Only problem was the reverb unit, referred to on the
    diagram as a dotted-line box labeled "Reverb Unit".  We didn't have a
    clue - we didn't even know they used springs.
    
    I robbed speakers from every TV and stereo that wasn't nailed down to
    make big wooden speaker cabinets and immediately alienated ALL of my
    neighbors.
    
    Oh, there was one other problem.  We never mounted the chassis on
    anything, so to pick it up, you just grabbed the aluminum and wrapped
    your fingers up under it, sometimes putting fingers into the wiring. 
    If you'd just shut it off, you could grab onto some filter condensers
    with enough juice to reinitialize your nervous system.
    
    Charlie

    Anyone have schematics for some decent delay and chorus designs?
    
    Mike

    
    I have an old schematic for an analog delay/chorus unit, but forget it. 
    I tried building it and *almost* got it to work (had extreme hiss
    problems I couldn't get rid of).  I spent about $50-60 on parts. 
    Cheaper to buy a stomp box.  I got a DOD analog delay stomp used for a
    whopping $20. 
    
    Also tough to get the ICs you need, almost everyone used the old
    SAD-512 and SAD-1024 from Reticon, these are hard to locate these days.
    
    Do-it-yourself FX have kind of priced themselves into oblivion.  How
    can you compete with $150 digital FX units?
    
    						  Brian

    	 
    	You can get a variety of Bucket Brigade Devices, including
    	the 512 and the 1024 from Digi-Key. They are still made
    	by Panasonic. The 1024 is about $9, Part# MN3207 for the
    	low noise, low voltage operation version. They have versions
    	up to 4.1 sec. The data book for all the Panasonic BBD's
    	is $3.50. Call Digi-Key at 1-800-344-4539 for a catalog.
    	    The Engineers Notebook II by Forrest M. Mimms III is
    	available at Radio Shack and has a complete schematic for
    	a Flanger/Phasor/Reverb using the SAD-1024, a TL084 quad
    	op-amps, and a 4011 quad nand gate.
    
    	Neal
    

    Thanks for the info, Neal.  One of the hardware engineers here has the
    Digi-Key catalog.  I've placed an order with them already for Kitty
    Hawk replacement components.
    
    Mike

   Anyone got schematics for either a Bandit 65 or a Studio Pro 40?  Both
   models are about 10 years old.  Any pointers would be appreciated.

   -- Sam

Mike,

	I tend to agree that buying is the best decision, I gave up and and
bought a BOSS delay and a chorus stomp boxes.

However I do have the schematic for the BOSS delay unit. It uses the MN3005
chip.

It is a simple little schematic, and you will have the advantage of 
re-designing it to place the unit in the amp send/return loop for improved 
noise performance (not that I find this a problem). I have re-built all my 
stomp boxes in a rack for send/return operation.

Mail me if you want a copy.

Dave Litten @ SBP  (UK)

I've got a friend that has old text books from engineering school on tube 
design, etc.

I want to study them some and would like to get some schematics of some of the 
classics for examples.

Anybody got schematics for a Deluxe, some good Marshall, et al, that you could
copy and send me?

Thanks to all,

Will

    
    
    
    
    
    
    	Will, I have "The Tube Amp Book II" and it has all those schematics
    in it..  if you can't get them anyplace else send me your list and I'll
    send you copies..
    
    Gree Vee

       
       
       
       
       
       A friend of mine has a mid 60's Vox Tone Builder he wants to
       rebuild.  Anybody got schematics or info on this beast?  Anyone
       know part numbers for the transistors?  (in TO-5 cans)
       
       
       
       
       
       

    The transistors are most likly replaced with ECG102's, or ECG123's,
    I'll hunt up a schematic for ya if I got it.
    
    Jay Tashjian