Introduction: Modify Your Wah Pedal

Picture of Modify Your Wah Pedal

After making my talk box I started surfing the web for other guitar related things I could do myself. I found loads of info on the Dunlop GCB-95 wah pedal. This Instructable will walk you through all of the modifications I made to my wah pedal...

*True Bypass Mod
*Volume Boost Mod
*Wah-Volume Pedal Mod
*Vocal Mod
*Midrange Mod

After having completed all of these mod and a few others I recommend doing them one at a time and testing in between mods so if you don't like something, you can easily reverse it.

Your gonna need some basic soldering tools...
-good soldering iron (mines a Weller WESD51D I got for christmas)
-wire cutter/stripper
-helping hand (a must!!)

also the to wire anything to the board itself you will need 24AWG wire

Step 1: Research

Picture of Research

I think this is a big step in all of my projects. You don't want to just jump in without input from multiple sources. A few of the site that helped me were... click "FX Technology
-Technology of the..." in the upper left

These are some pictures I found useful...

Step 2: True Bypass

Picture of True Bypass

So when your have you pedal off it doesn't affect your sound right? WRONG!! You may have noticed that even when off some of you effect pedals "suck" the tone from your guitar. A better explanation can be found Here.

I chose to remove the input buffer because it seemed to be the most easily reversible and from what I read, sounds better.

1. Open up the case and remove the circuit board.
2. Desolder the components.
3. Desolder the switch.
4. Install the new switch. (i used a 3PDT switch. Check out ebay for good deals)

If you use a 3PDT switch you can also add an LED to you pedal but I didn't want to.

Check It Out

Step 3: Volume Boost

Picture of Volume Boost

This is one of the easier mods because If you've converted to true bypass, all you need to do is replace the 68K series input resistor with a lower value. I read that too low a value is likely to result in the pedal picking up radio interference. I made the mistake of following That_Pink_Queen's model almost exactly. Luckily this is one of the ones he made that sounds good.

Step 4: Wah-Volume Pedal

Picture of Wah-Volume Pedal

Now I'm sure we would all love one of these here, but if your like me you just need something that works and wont cost you your left nut. By adding a DPDT switch that disconnects the 4.7uF capacitor you can cancel the wah effect and you'll have yourself a volume pedal.

I got 50 of these babies on ebay for $10 w/shipping.

Step 5: Vocal

Picture of Vocal

This one is pretty cool because it allows you to treak the sound of wah itself.
"Replace the 33K resistor... with a 68K. This gives a more vocal quality to the wah. Some Vox Clyde McCoy wahs had 100K resistors here." -

I decided to go with That_Pink_Queen and use a 100k ohm lin variable resistor so I could dial in the sound I wanted. Or you can mess around with multiple resistors and a rotary switch. Your choice.

Step 6: Midrange

Picture of Midrange

"Replace the 1K5 resistor... with a larger value. This increases the midrange and helps if your wah sounds dull and muted when you rock the pedal back. Try 1K8 to 2K7. Higher values than stock also smooth out the bass-treble transition." -

So I replace my 1.5K (1k5 same thing) resistor with a 2.2k. Sounds fine but I since I did all my soldering in one go and the removed what I didn't like I cant say weather or not the difference was noticeable. Try it out for yourself.

Tip: Save all of the components you remove and store them in a container. That way if you want to change something back... you can.


TzvetanD (author)2017-04-25

Guys, I want to mod some cheaper Cry Baby and turning it as slose as
possible to sound like Cry Baby JP95 (John Petrucci signature one). Its
range is from 100Hz to 3.2kHz and sounds very specific and lovely! Can
it be done?

GlennE3 (author)2016-11-30

I'm thinking about adding a 100k trim pot to replace the 33k resistor next to the inductor for the vocal mod, as I have no idea if 68k will be enough or if I'd like it a bit higher. The trim pots all seem to have 3 legs though, and the resistor is only 2, It looks like you added a full size trim pot to your wah, and ran the wires from the resistor to it. How do you wire the trim pot? Which two lugs do you use...? Thx...

koolkarlnz (author)GlennE32017-01-23

The two legs you would use are the center (wiper) leg and either of the outer legs. The outer leg that you use will change which way you turn the potentiometer to get higher or lower resistance depending on orientation etc. I would recommend being careful when using a trim pot that goes down to 0 ohms as this will result in no resistance which can potentially cause a short so be cautious and perhaps make sure that doing this would be safe. If you put another resistor in series with the trim pot you would definitely be safe (i.e keep the 33k pot and wire it to one of the legs of the potentiometer), this means you will have a minimum value for your resistance and would make it impossible to cause any shorts.

koolkarlnz (author)koolkarlnz2017-01-23

If you want it to turn to the right to increase the resistance look at the potentiometer with the shaft facing towards you, use the center pin and the pin on the left. (Sorry I had to reply twice, took me a minute to think about it)

ShaneH90 (author)2017-01-22

spaminmotherfuckers. i allow them my fb profile to download the steps , you have to pay or sit there for half an hour taking notes. THats a big "up yours Jack".

James Haskin made it! (author)ShaneH902017-01-22


ShaneH90 (author)James Haskin2017-01-23

yeah man, I wanted to download all your advice in one go along with the pics so I could actually use it (without spending half an hour taking notes or screeen shotting everything) and I would either have to pay for premium membership to download. THat is just fkd.

mauricioardiles (author)2016-08-04

Hi guys nice too meet you, i am new on it (sorry for my english i am from Argentina) and i would like to know if you know what kind of mods can I make to a dunlop db-01 dime from hell?, I have got one since febraury and honestly i think it is a big and expensive piece of garbage, everybody say that it is very configurable, etc, but the true is that this wah with a distortion sounds like waaah and only till the 10th fret, I am looking for a big waaaaaaaaaaaaaaaaaaaaah like the sound of arch enemy, petrucci, etc. I know it is possible to make a true bypass but i am trying to find another mod like the vocal mod, it is possible in this wah? do you know any other mod??

Thanks in advance

HarveyA5 (author)mauricioardiles2016-08-14

Look at all the links for ideas on what to change to get the frequency range/performance you might want, but also consider where you place it in the chain. Wah is usually before all fuzz/OD/distortion devices, but you may want to place after any/all of them to get huge variation. Also a compressor after might help. Just some ideas....

mauricioardiles (author)HarveyA52016-08-17

Hi Harvey, a few days ago I wrote to dunlop support and the answer was really funny, they requested me a video with the issue, then I send it and to be honest it has a bad quality then they send me the response : "

The pedal is working correctly. Sorry that you do not like the sound.

Best regards,


Jon Fryman

Electronics Technician

Dunlop Manufacturing, Inc.



So I am not really happy, I was reading about the available mods and I found a guy who solve the issue changing a 4,7uf capacitor for a 22uf, I will try this mod with help of a friend, we will also try the vocal mod, the thing is that the resistor are SMD and that can be hard to change. If it works I will make it true bypass and if it don´t y will try to make my own wah using it case


NoahT11 (author)2016-04-10

What do the pins at the top of the circuit connect to exactly? Thanks

KewlB (author)NoahT112016-04-25

they run up to the pot and switch. two of them run to a 9v battery connector.

WhittD (author)2016-03-03

JaimeB5 (author)2015-08-04

I see i am a few years late but just finished the true bypass led mod on my 535q wah pedal & wanted to put an exterior pot for control for my boost control since my wah is a older model that has it located under the pedal. I have studied many of the wah mods but cant seem to find anything on this & there is little on the 535q, any advice?

ahazbun (author)2012-11-23

And if you break your pedal, get a new one! Simple wah pedal by Source Audio.

ArtXander (author)2011-09-08

Hi! I haven't understand how to wire the pot. I must connect the pot where there is the 33k resitor? 1&2 lug together to a side and 3 to the other?

angelofdeth68 (author)2011-07-26

Great instructable. thanks.

jphoton (author)2011-04-30

hi guys, lifting the ground of the cap in question will indeed kill MOST of the wah effect, but it will not make it a true volume will make it a tone pedal for all intents and purposes. it will kinda work on volume...sort of...but it won't be a true volume pedal. tried it on my old gcb95 long ago, was too lazy to un-do can be interesting, but don't be disappointed when it doesn't work the way you'll probably envision. good luck mate!

Jezrael (author)2011-01-13

Wich resistor do you recommend to replace the 68k resistor? or, wich value did you use? Greetings

thewizard42 (author)2010-09-02

Do you mean spdt? or does it have to be double pole, because i do not see why you would need the second pole

overdrive555 (author)2010-06-10

hi boys, why u dont use a trimmer to replace 1.5resistor?

butthead95 (author)2008-06-03

Buy the Crybaby From Hell it has most of this stuff inclyuding a five selection knob for dif ranges

Yeah, its also 200 dollars.

alenchence (author)2010-05-22

I have a problem:when I click on the link for the installation of a new switch,it says the instruction is no longer available,so please help me out!I would like to do this mod,tone sucking is driving me crazy!

mesaiphoneguy (author)2010-03-05

 will this also work on a 535Q crybaby wah pedal?

stupidityisagift (author)2009-11-28

hey, can you mod it for volume another way besides the capacitor? i have a snarling dog wah and want to mod it for voume, and i doubt the capacitor switch will work the same

rcrane (author)2009-08-22

Hey, I am stuck. I have a green board like the one above and it is labeled 'E". I did the following: Removed old switch Removed the buffer components replaced the 33k with a 68k replaced the 1k5 with a 2.8k installed a 3PDT switch My problem is that I only have four wires to attach to the switch: 2 blue 1green 1purple I dont see any pictures showing the installation of the 3PDT usingmy board. Do I need to install wires where I removed the buffer and solder that to the switch? I don't know how to configure the wires on the switch. Help!

James Haskin (author)rcrane2009-08-22

I added a picture from step 3 to step 2. My pedal is also a green E type board but all of dunlops circuits are so similar (except fro maybe Dimebag's Wahs from hell) that the wires from the top of the board to the pot and switch are the same.

Using switch diagram 5 as a reference tool.
Both PCB and Pot Blue to 7
PCB Purple to 8
PCB Green to 9 as well as a jumper to 1
Connect the transistor jumper to 2
and the resistor jumper to 3

rcrane (author)James Haskin2009-08-30

Got it! Sounds much better. Thanks for your help. I am still experimenting with the pot range. But MUCH more vocal and quiet! thanks again

rcrane (author)James Haskin2009-08-23

James, Thanks for the quick response! So that explains how to wire the existing wires. I only changed two resistors and changed the switch, so I will attach the wires like you said and then I just need to add two wires to the area that I removed the buffer and wire them to 3? rcrane

abehughesmusic (author)2009-08-26

Hey I just did the Wah/Wolume mod, (that's the only mod I did). Admitably I didn't do a great soldering on the board, but all the contacts seem to be solid and the pedal basically does as it's supposed to. The problem I'm having is that in the Volume setting in the pedal doesn't get all the way quiet in the far back position. Did I miss something? This was my first attempt to mod a pedal and except for that one thing, which I'm really not going to loose sleep over, it seems to be working and not giving me any particular trouble. Thanks for this instructable. After I do some more work, I'm going to try a keely mod I found for my tube screamer, and (fingers crossed), try doing the seeing eye/ ultra mod for my DS-1. Thanks again.

When you move the pedal your actually turning that big greasy pot. the range of the pedal is shorter than the range of the pot. Basically, when engaged, the pot is never fully on or off. Look up how to calibrate a wah pedal and you'll see what I mean. The fact that it doesn't go dead silent doesn't bother me.

somerockenguy (author)2008-12-10

could you elaborate on this i would love to do this mod (wah-volume mod) but i only partly get how to do it. you think you could do an instructable on just that or point me to a web site that has a how to on it?

Ok so here the deal, sometimes people say they have "broken" wah pedals. They will say that its only changing the volume. Well that happens when this capacitor blows/dies/goes bad. So what I did was desoldered it from the board and hooked up two wires to it (pic1). Then I soldered the wire next to the gray (negative) to the middle switch. Then I soldered a lead running from the switch to the left hole (negative), and soldered the other lead on the capacitor to the right hold on the board. The only thing that matters is the Polarity. You can have the switch on either side of it. If you still don't get it PM me you # and Ill give you a call. (I just don't fell like taken pictures right now)

mrwonkaland (author)James Haskin2009-07-24

hi. i dont know much about fixin these electronics but i can learn pretty fast. i was wondering if you could help me with my dimebag wah pedal. its not crying anymore. and that makes me sad. i thought it was the pot. but on ur blog u say its the capacitor. id rather take ur word over my assumption. id really appreciate it if you could help me out. u say to leave a #. i dont know if you were talkin to someone else or just offering yourself. but in any case, my number is 602.295.0008. my email is thx for your time.

stupidityisagift (author)2009-07-12

hey, im a lil confused. is this mod for switching from the wah, to the volume mod, or is it wah volume combonation? thx

The switch cancels out the wah circuit and turn it into a wah pedal. The rest of it changes the tone of the pedal.

oweng4000 (author)2009-07-18

I had an idea for a mod that i hope will work. a switch on the side in order to switch inductorPr

James Haskin (author)oweng40002009-07-19

Sounds like the MXR Custom Audio Electronics MC-404 Wah. Check it out.

trgz (author)2009-06-04

I've got an old Cry Baby that, way back in the 80's, I modded it to be a Wah/Volume and I only used a couple of parts in the mod, sadly though I can't remember what they were but I suspect I managed it with a simple change to the stomp switch and/or pot (multi-way versions),- it might have shorted out/bypassed a section of the circuitry like above (James H). It's up in the loft but I un-modded it when I went thought about selling it (20 years or so ago).

mabu4237 (author)2009-04-25

Where does the switch for volume wah switching go?

spiceyweasel (author)2009-04-13

Sick! I've got a vintage Morley Distortion/ Wah pedal that also can be used for volume control. It'd be cool to add a few ring-dings to it. Thanks.

psychodeathmonkey (author)2009-04-11

Hey anyone know what i need to make my wah into a wah/ring modulator like the snarling dogs mold spore or the arctec wish wah? I like the pedal ive got and dont really feel the need to buy another pedal. so anyone know what id need to do it. I pretty much know the basics , pots ,wires, and some kind of resisters, capaciters and all that stuff so. anyone help me out?

ReoTheYokel (author)2008-12-02

You can prevent "sucking" the tone by using one of those True Bypass pedals. Or something like that. Justin Sandercoe reviewed it in one of his videos on Youtube. But, yeah, this is cheaper.

James Haskin (author)ReoTheYokel2008-12-02

The way I wired it, using the switch, this pedal is true bypass.
Oh this is pretty cool. I actually like leaving my wah in a position at times but this it pretty cool. I'll buy one of these for the dimebag wah from hell. It would be great soloing.

mondaymonkey (author)2008-11-23

I splurged and got myself a Dunlop 535Q. Love it to bits, but need a light to tell me if its on or off. I'm probably just going to have another push switch connected to a small battery and LED mounted on the underside of the foot control pedal

avibank911 (author)2008-10-23

dono if this is the right place to ask but- how do i add a string of led's to my volume pedal to indicate the postion of the potentiometer

James Haskin (author)avibank9112008-10-23

Idk dude, personally I don't think its worth the effort.

no food please (author)2008-07-12

I'm looking into doing this, but I have the dime cry baby custom (model db-02). It contains mostly smd components and all of the circuit board traces are covered up and really hard to see. I can't find any pictures of other people working on it, or any circuit diagrams for it. There are some spots that don't have have anything soldered to them, but have traces leading up to them and labels (e.g. "C3" or "TP1").

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