Modify Your Wah Pedal

by James Haskin in Circuits > Electronics

281086 Views, 193 Favorites, 0 Comments

Modify Your Wah Pedal

DSC01345.JPG
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)
-solder
-wire cutter/stripper
-helping hand (a must!!)

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

Research

gcb95.jpg
pcb5.jpg
articlewahmods7zv.jpg
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...

http://homepage.ntlworld.com/s.castledine/greenfuz/wah.html
http://www.stinkfoot.se/andreas/diy/mods/dunlop.htm
http://www.guitarzone.com/forum/index.php?showtopic=176864
http://www.geofex.com/- click "FX Technology
-Technology of the..." in the upper left
http://www.geocities.com/overdrivespider/tb.htm
http://www.geocities.com/j4_student/schematics.htm

These are some pictures I found useful...

True Bypass

DSC01134.JPG
DSC01139.JPG
DSC01133.JPG
DSC01136.JPG
DSC01137.JPG
DSC01140.JPG
DSC01141.JPG
DSC01143.JPG
DSC01147.JPG
DSC01148.JPG
DSC01146.JPG
DSC01150.JPG
1561_dia5.gif
articlewahmods7zv.jpg
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

Volume Boost

pcb5.jpg
articlewahmods7zv.jpg
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.

Wah-Volume Pedal

DSC01307.JPG
DSC01306.JPG
switchdpdt.jpg
pcb5.jpg
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.

Vocal

gcb95.jpg
articlewahmods7zv.jpg
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." - http://homepage.ntlworld.com/s.castledine/greenfuz/wah.html

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.

Midrange

DSC01340.JPG
DSC01347.JPG
DSC01345.JPG
"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." - http://homepage.ntlworld.com/s.castledine/greenfuz/wah.html

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.