Modify Your Wah Pedal





Introduction: 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

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

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

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

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

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

"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.



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Thanks ! Big help.

I possible to add an extra mod recreating the wahmmy effect ?

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?

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...

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.

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)

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

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....

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


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

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