Introduction: Foot-on-pedal / True Bypass Crybaby Wah Mod

Picture of Foot-on-pedal / True Bypass Crybaby Wah Mod

UPDATE: The old wiring diagram contained errors (sorry, I wasn't too familiar with electronics and wiring diagrams, this was one of my first projects and my first instructable). There were also questions about the blue wires going to the wah pot, I drew the wah pot to make things clear.

This makes your Crybaby wah switch on when you put your foot on it, and turn off when you remove your foot!. It will also be equipped with true bypass. That means that the circuit is actually bypassed when the wah effect is off, instead of passing through its transistor bypass circuit (that ruins your sound, removes clarity, makes distortion sound like a bad fart, etc).

If you might want to control your wah the original way for some reason, then there's a miniswitch on the side that lets you choose between the two modes. When the wah is in foot-on-pedal mode, a green led lights up to indicate this. I also placed a red led that indicates that the wah is on AND in original mode. The thing I hated most about the standard crybaby is that you could not see whether it was on or not!

-- VIDEO --

Step 1: Buy Parts

You have to buy a few parts for this mod. I bought them all together for about 10-15 euro's:
- 3PDT stomp switch, to replace the stock one
- green 3mm LED
- red 3mm LED
- 350 ohm resistor*
- 390 ohm resistor*
- 3PDT miniswitch
- DPDT mini momentary switch, with button.
- thin electrical wire
- superglue or two led holders

Tools you (might) need
- plyers, for cutting the wires and tightening the nuts
- a wire stripper. You can use the plyers if you dont have one, but be careful not to cut the wire
- a drill and a set of drill bits
- soldering iron
- screwdriver

*If you can't find these specific resistor values, take the the nearest value you can find. A higher value is good, but don't get significantly lower because that will cause the LED to burn out. Also, if you think the LED's are too bright, try higher value resistors such as 1K or higher.

Step 2: Replacing the Original Switch

Put the wah on its back and grab a screwdriver. Unscrew the four screws holding the baseplate.

Now, cut the wires coming from the stomp switch. Cut them close to the lugs, we still need these wires! Now, remove the switch (use plyers to unscrew the nut).

Put in the new switch, and test it by kicking down the pedal. You should hear it click when you apply firm amount of pressure. Adjust the height with the nut and washers to get it working. You don't want to have to apply 10 tons of pressure on the wah to turn it on, but on the other hand, you don't want your wah to switch off when you just press the pedal down right? Fiddle around a bit and find out what works best for you.

Step 3: Drill Holes for New Components and Fitting the Leds

Picture of Drill Holes for New Components and Fitting the Leds

Now it's time to start drilling ! This is probably the hardest part. You have to drill through solid steel, and Its pretty hard steel too. I strongly recommend a drill press for this, since it is more stable and powerful.

Lets start with the biggest hole: the one for the momentary switch. It has to be drilled right through the top surface of the pedal. The best spot to drill is probably between the 'A' and the 'I' (there's AMPLIFIER on the left and INSTRUMENT on the right). Grab a drill bit (i think it was 5 or 6 mm, can't remember actually. Measure the switch shaft to find out) and drill right through it. Don't rush, just drill gently with a firm amount of pressure on the drill bit.
Now take a slightly bigger drill bit, and use it to chip away some extra rubber around the hole. Don't drill into the metal this time. Now you have space to put the nut for the momentary switch. Press it in there, if it doesn't work, chip away some more rubber.
We're not going to place the momentary switch yet. You won't be able to wire it anymore if you do.

Now the side of the pedal. We need 3 holes: 2 3mm holes for the leds, and a hole for the miniswitch. I drilled them next to the output and the DC in. Check out the picture below. Put the switch through the hole and screw on the nut.

Now, lets fit the leds. Grab one, and just force it into the hole. You can also use special led holders, these require slightly bigger holes. Then put a small drop of superglue on the led and wah casing (at the inside!). Wait 2 minutes and your done, these leds won't be going anywhere!

Step 4: Wiring the Thing

Picture of Wiring the Thing

Ok, soldering time. Use my wiring diagram. It should be clear from that. Don't worry, you will not destroy your wah if you mix up wires.

- Pay attention to the C NO NC symbols on the side of the momentary switch
- pull the wires for the momentary switch through the pot hole, and solder the switch outside the casing. This because you have to install the momentary switch with the wiring already attached to it, and it can't go through the pot hole (learned that the hard way)

This step will keep you busy for a while believe me ;)

Tip: use different colored wires. It makes debugging a LOT easier, since you can track where the wires are coming from.

After you've wired everything, install the momentary switch. Use both hands to screw in the momentary switch (you're turning the switch, not the nut. The nut is locked in place by the rubber). The switch wires now twist into a nice solid string. Be careful not to damage the wiring!

Step 5: TEST

Lets do the first test!
Plug a guitar cable into the instrument input, and hook up a 9V power supply (battery or adapter, doesnt matter). The pedal is now powered. If the green led is on, flick the miniswitch. If you see no green led light up at all, check your green led. Its probably wired in reverse, so swap the leads and try again. If your green led works, press the momentary switch. The green led should not go off, if it does, you probably made a serious wiring mistake. If everything works, flick the switch and test the other mode:

- NO LEDS ON - The pedal is probably in the original switching mode. Stomp the pedal down. The red led should light up. If it doesn't light up, its probably wired in reverse. Swap the leads and try again. Also, try to push the stompswitch down with your finger. The switch might not actually switch because it's not mounted properly. Try raising it if this works.
- RED LED ON - The pedal is in the original switching mode. Stomp the pedal down. The red led should go off. If is doesn't, you've made a wiring mistake. Maybe you bypassed the switch somehow. Recheck the wires with the diagram. Also, try to push the stompswitch down with your finger. The switch might not actually switch because it's not mounted properly. Try raising it if this works.

If this all works fine, there is a big chance that the actual wah will work as well. Plug in a guitar and turn on your amp. Don't crack it up yet, it might squeal or buzz. THIS WILL NOT KILL YOUR AMP OR GUITAR, don't worry. Try the wah in both foot-on-pedal and standard mode. Possible problems you can face:
- buzz, and no guitar sounds. Solution: a wire is not connected. If it doesn't work in both modes, with wah on and off, it is one of the main wires coming from the circuit board, going to the miniswitch. If it doesn't work in one of the two modes, check out that mode for loose wires. If it only works when the wah is off, or only when the wah is on, check the wires on that side of the switch.
- squeal. solution: you mixed up the two wires from the wah circuit to the miniswitch. Just swap them and it should work fine. Again, if it only works in one mode, just check the faulty mode and those particular wires.
- nothing. Just silence. This means there is a shortcircuit somewhere. Check if there is any bare wire that hits another wire or lead. Also, check for mixed up wires. Again, try to isolate the problem by testing all modes.

Don't give up. Testing is always the hardest (and most boring) part. But eventually you will get it working!

Step 6: Have Fun With It!

Picture of Have Fun With It!

Congrats, you succesfully finished your wah mod! Have fun with it ;) !

here is my video
-- VIDEO --


paul.oakley.92 (author)2014-11-27

Don't know if you still check this (the last comment was 3 years ago!), but I'm slightly confused... Where the wires are connected to the components on the circuit board, do you remove that end of the component from the board (where you attach the flying lead), or is the wire a junction from the component?

mnuru1 (author)2013-10-21

Great mod!I have a question tho, if I wanted to keep the buffered bypass but do everything else in the mod, what changes would I make to the current schematic. Thanks!

lsalles (author)2011-03-10

In this diagram, can I withdraw the buffer components or this is not necessary and that will be true bypass even with the buffer there?
Thanks, bro!

KoenB (author)lsalles2011-03-12

I believe the buffer circuit is also bypassed, but i'm not a 100% sure. You can test it by plugging in the wah with out power and turning it on and off. If it really is true bypass, you'll still be able to hear sound coming out of the amp when the wah is turned off.

Fopat (author)2010-10-05

Thanks for this mod! The momentary switch to enable the wah is a very good idea!
However, I think one step is missing to make the mod really true-bypass. From what I have read on the 2 websites below, to be true bypass, the circuit between the input jack and the buffer input needs to be cut:
Else, the green cable soldered on the capacitor has no use. Or maybe I misunderstood something?

mtstreit (author)2010-07-24

can you use 5mm LED lights instead of a 3mm LED?

rpdiggs (author)2010-01-22

I found this mini momentary DPDT switch for the US..  Certainly hard to find.  Haven't ordered it yet but think it's my best option.,4768.html

barkley (author)2010-01-07

Where can I find a DPDT mini momentary switch?
Ive looked everywhere!
The site mentioned by somerockerguy doesnt have them and niether does that dutch one you mentioned!

KoenB (author)barkley2010-01-09

My local electronics shop sells them, but i dont know where they get them from (an they probably wont tell me). I tried a bit of googling using the image search and found this after a while

KoenB (author)KoenB2010-01-09

... i dont know if theyre shipping worldwide though..

ludoheavy (author)2009-10-20

tank you for the new diagram!!

But i have the same question of Link0126, where goes the blue wire from the harness?

KoenB (author)ludoheavy2009-10-20

I can image this being confusing. I'll update the schematic again to make it clear. It should be up in under an hour.

stupidityisagift (author)2009-07-12

can u do this to a modded cry baby that has been modded as a wah/volume pedal?

KoenB (author)stupidityisagift2009-07-12

Not 100% sure but i think it will work. All the volume pedal mod does is removing one capacitor, no major circuit changes, so it will probably work.

lainage (author)2009-06-24

Can you post a link to the mini-momentary switch supplier? I cannot find a mini one anywhere. Awesome mod by the way.

KoenB (author)lainage2009-06-24

I bought it at my local electronics shop here in town. I dont really know any online suppliers, maybe google can help you ;)

go2ldook (author)2009-04-23

Your wiring schematic is wrong in terms of the momentary switch. Here is how it should go:
4 5 6 (looking at lugs with the common to left, normally closed to right.
1 2 3 and lugs numbered as shown)

1= Purple wire (Output to amp, to middle lug of middle row on 3pdt switch)
2= Blue wire (The effect loop return, goes to wah pot)
3= Green wire (Input from guitar, goes to the PCB harness)
4= Green wire (The effect loop input, goes to top right lug of the 3pdt switch)
5= Solder your jumper wire from 5 to 3)
6= No wire here
With this arrangement the switch (as long as it is the same type of momentary switch with the same C-NO-NC orientation as shown in the drawings in the instructable) should work as expected.

As drawn in the instructable the wiring diagram results in no signal with foot off (C-NC connected, which as drawn means the guitar input flows to the effect loop return). With the Foot On you get Clean (C-NO connected, the guitar input connects to the amp output). At least this is what I see...I had wired it as shown in the instructable, and posted stating that I had no signal foot off, and wah with foot on, but I may have been frustrated at the time and wrote the wrong thing...if you follow the signal paths, foot on should give you a clean signal as it is currently diagrammed.

Also, for other who know nothing about these switches, the lug are flat. To orient the 3PDT stomp switch and 3PDT mini toggle switch correctly for wiring as shown in the instructable, the lugs should look like this:
I I I ON _ _ _ ON
I I I for the stomp, but like this: _ _ _ for the mini switch.
I I I _ _ _

I think that is correct for all stomp switches. For the mini 3PDT toggle, you just need to make sure the "ON" throws are on the left and right as shown.

Sorry to be so verbose, but I am not an electronics hobbyist, so having this spelled out in the instructions would have saved me a lot of pain. No offense to the author...this is a cool project, and thanks for posting it!

go2ldook (author)go2ldook2009-04-23

Sorry, my attempt at drawing a schematic for the 3PDT switches failed when it got reoriented at posting! Hopefully people get the idea.

go2ldook (author)2009-04-21

Have wired this up and checked over it numerous times. My LED's light fine. With the momentary switch I get no bypassed signal, but when I depress it I get the wah. If I switch back to standard switching, I get the wah effect whether the switch is turned on or off. Can't figure this out. The two wires that go to the they go to the same lug on the pot that the blue wire to the PCB goes to? Any ideas what I have done wrong?

link0126 (author)2009-03-25

do the two blue wires coming from the wah pot indicate the one wire from the pot as well as the other one coming from the harness? does it matter which one goes on which switch? thanks

link0126 (author)2009-03-24

how do you mount the momentary switch without a nut on the top?

KoenB (author)link01262009-03-25

There is a nut but its 'submerged' in the rubber pad so you cant see it. I chopped away a little bit of rubber with a drill bit (i believe it was 7 mm) and pushed the nut in the hole. Be careful not to drill the metal because and ruin the hole for the switch post. Then i grabbed the switch and screwed it in from beneath (turning the switch, not the nut)

greatnameless1 (author)2009-03-16

I'm just saying, why? Instead of going to all this trouble, don't buy a crybaby in the first place! Get a Weeping Demon - They sound great, they already do this, they're spring loaded, they're customizable, and they're built to withstand armageddon. Better than spending your money buying replacement crybabies..

mikka1984 (author)2009-02-23

hey, i am doing you wah pedal mod at the moment and a bit stuck the wiring is correct as far as i can see, i checked and rechecked it and it all seems fine the issue i get is kinda loud constant crackling sounds and i can barely hear the giutar through that i got a few questions 1st does it matter which way i wire the switches ( i know where the middle is but not sure if its the same if i wire it if i turn it on the other side ie mirror( 2nd on the wiring diagramon the wah circuit board u have a comment solder to capacitor lead. i soldered the wire from the back of the board so the wire would be out of the way, is that correct? 3rd once i removed the blue wire to the stomp switch i get a blue wire that leads to wah pot and to the circuit borad. amd i suposed to keep this way or should i omit the blue wire that come from the circuit board? thanks for your help

mikka1984 (author)mikka19842009-02-23

ok just a quick update
after fiddling with it for about 3 hours (unsoldered it and soldered it back all together) same result, when i plug it in loud crackling sounds and i can barely hear my guitar throught it. thats the same effect with all positions of stomp switch and 3pdt switch. also noticed another thing... the leds dont turn off completely when i change it, the light dimmers but it still on on both :(
im getting whipple wah mod in a few days so im gonna try trouble shoot then by 1st converting it back to original state and see if i can solve the problem then, but at the moment .... no joy :(

mikka1984 (author)mikka19842009-02-23

another quick update just removed the 3 switches and leds and installed the old stop switch in the pedal... al works find, very confusing rechecked the wiring again, everyhing seemes to be correct tested all switches, all work perfectly im getting a little bit angry now

KoenB (author)mikka19842009-02-24

Man this is weird. It sounds like a bit of a shortcut, since the leds stay on all the time (sort of). Can you send me some pictures of the wiring? Maybe it makes some sense. My email is Did you get any good results with just installing the 3DPT stomp switch (so in fact just adding a basic true bypass mod) ?

mikka1984 (author)KoenB2009-02-24

ok email sent, thanx for your help :D i will host the original size images this evening

KoenB (author)mikka19842009-02-24

Have you tried putting the circuit back in the housing? A lot of pedals use the metal housing as a ground lead. This might be the problem. If not let me know

mikka1984 (author)KoenB2009-02-24

check ur email :)

itsachen (author)2008-08-01

hey dude, love the instructable first of all where do u get ur 3PDT switches? i cant find any in my local radioshack, only online... thanks

somerockenguy (author)itsachen2008-10-18

i got mine here there based in the U.S. and they have all the parts to do this mod.

KoenB (author)itsachen2008-08-01

I bought mine online at . Great shop, but a dutch one, so probably not your thing. 3PDT switches are hard to find, so I guess you have to order them online.

vitorp07 (author)2008-08-20

Hi,nice project and thanks for sharing it. i just have a question,could you help me out or pointing me to find a DPDT mini momentary switch,i just can't find one that seem to do the job if you have a link for ebay or something online it will be much appreciated. THANKS

KoenB (author)vitorp072008-08-20

I got mine from a local shop here in Holland. But since you're probably not dutch, you have to find a different shop (obviously).,4768.html I found this one by google. Yes, they are expensive. Mine was 5 euro's.

vitorp07 (author)KoenB2008-08-20

Hey thanks,they don't ship out of USA and i live in Canada but i sent them an email asking if they could sell me that switch,i hope they can...

KoenB (author)vitorp072008-08-21

And if they don't, try this one

I think they ship worldwide, not sure though.

somerockenguy (author)2008-07-14

i finished you mod today it took about 4 hours. i am very happy with it i just need a diffrent momentary switch because mine is so high and makes poping noises.

here are pictures

if you want to use any of these pics you may.

KoenB (author)somerockenguy2008-07-15

Looks nice! But I see you've used a big momentary switch. Try to find a momentary miniswitch, they are much smaller (and they pop less). These have small plastic shafts, so you can cut a bit off if you think its too high. I don't know if its a good idea to use your pics too. It might get a bit confusing with the different switches. And I am too lazy to add them too ;)

somerockenguy (author)KoenB2008-07-15

the site i bought every thing from only had the one momentary switch so im stuck with it un till i find some place localy that carrys them.

modmaniac (author)2008-07-10

Thanks, And, great instructions and diagrams. Best on the net!

modmaniac (author)2008-07-10

In your parts list you have the momentary switched specified as a 3pdt and the mini toggle as a dpdt but in your wiring diagram you show the toggle as a 3pdt and the momentary switch as a dpdt. I'm guessing that the diagram is correct and the parts list is wrong. It that the case?

KoenB (author)modmaniac2008-07-10

Yes, that was the case. Thanks! It's been corrected now. So you need a 3DPT miniswitch and a DPDT momentary.

somerockenguy (author)2008-06-21

For the 350 ohm resistor would a 10 watt 350 ohm resistor with 10% tolerance work and for the 390 would a 1/8 watt 390 ohm resistor with 5% tolerance work? These are the only 350 ohm and 390 ohm resistors i could find.

KoenB (author)somerockenguy2008-06-22

Yeah they will work. The Wattage and tolerance doesn't matter at all in this case.

somerockenguy (author)KoenB2008-06-22

good then ill be building this in about a week when my shipment of parts arive.

KoenB (author)somerockenguy2008-06-22

Cool that you're going to do my mod! Can you post some picture links when you're done ?

somerockenguy (author)KoenB2008-06-22

shure. any thing you want in particular? if you need pics for the steps ill be happy to give them to you if you want them. i wont be done for about a week i just ordered the parts. those 3pdt pushbuttons are not easy to find.

KoenB (author)somerockenguy2008-06-22

Not anything in particular, just wondering how your mod will look ;) I ordered my 3pdt at, but thats in Holland. They are really hard to find!

somerockenguy (author)KoenB2008-06-30

the guy im ordering the parts from forgot to order the parts from a supplyer on two ocasions so to day he said he has every thing in stock ill order tha parts tomorrow and im going on vacation from the 5th to the 12th so i hope the parts will be here by then and i sould be done by the 13th. this is taking longer than i hoped but if all goes well and i don't cover the wah board in solder ill have happily compleated you instructable.

About This Instructable




Bio: A guy with a passion for playing guitar, engineering and of course DIY... and beer too.
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