Dunlop GCB-95 "FatWah" Mod
By Paul Marossy
This is a mod to the Dunlop GCB-95 CryBaby wah pedal that was devised by Paul Crowther of Crowther Audio, maker of boutique guitar effects such as the "Hotcake" and the "Prunes and Custard". It's a really simple mod and it sounds pretty good, too. It only took me 20 minutes to perform this mod and it involves lifting one end of two components on the PCB and adding three new components (four if you add the "fatwah bypass switch"). It makes the wah sound fatter and smoother, it seems by taming some of the piercing highs and emphasizing the mids/lows a little more. It also seems to make it sound a little more vocal as well. This is accomplished by adding a bypass cap on the emitter of the input buffer transistor, relocating the point of connection of the negative terminal of the 4.7uF cap near the inductor and adding a couple of new resistors.
Here is the basic GCB-95 CryBaby circuit. The transistor labeled "MPSA13" is the transistor for the input buffer. We will be lifting the ground end of the 10K resistor on the emitter of this transistor and the 4.7uF cap near the 500mH inductor.