Crybaby GCB-95: How to mod your wah pedal

If you don’t like how your stock Crybaby wah pedal sounds, there are some reversible modification you can do to change the way it sounds. I gathered info and followed DIY Guitarist and WahWah.co.uk instructions, and I highly recommend you do the same.

I got my CryBaby back in the early 1990s and I want to modify it to make it sound more vocal, and also to reduce the dull sound when the pedal is rocked back.
All you need is a soldering iron, some lead, pliers, a screwdriver, a few components and a bit of patience.

I’m not an electronics guru, but I know enough to dare replacing some components and see if I like the result. If I were a true expert I wouldn’t share my knowledge with you folks, I would sell my modified CryBaby kits instead and make money out of it :-)

The following directions apply to Dunlop Crybaby GCB-95 revision G pedals, but can be adapted to other versions, Google it. Here is how the PCB layout looks like:

Crybaby PCB

 

This is what I have done to my pedal:

  • Make the wah more vocal sounding – the 33KΩ resistor between the jack input and the inductor (which is that black, round component in the middle) is the component that controls the Q value, or the sharpness of the bandpass/resonance effect. Low values makes the wah sound flatter, while higher values makes it sound sharper and more resonant. I opted for a 68KΩ resistor.
  • increase the midrange – 1.5KΩ resistor near the sweep capacitor is replaced with a 2.2KΩ resistor. 
  • Increases the gain – 390Ω resistor near the transistor is replaced with a 270Ω resistor. This low value increases the gain a little too much for my taste. In front of a low gain pedal or low gain amp setting, the wah pedal acts much like a booster, and I don’t like it. I removed this resistor and went back to stock 390Ω, but your mileage may vary. You can try using a 470Ω resistor, like that found in the Vox pedals.

Crybaby PCB desc

Notice that I haven’t replaced the sweep capacitor. I tried with a 0.022uF capacitor to increase the bass response but the wah sounded terribly dull when I rocked the pedal back, causing the guitar to completely disappear in the mix with other instruments.
Even though I really liked how the new capacitor smoothed out the response between the bass and treble, I opted for keeping the stock component. I may try a different value in the future:

  • stock “sweep” cap is 0.01uF (which is 10nF)
  • suggested value is 0.022uF (which is 22nF)

I will get myself all of the values in between (12nF, 15nF, 18nF and 20nF) and do some experiments.

See also Replace stock Crybaby inductor with Fasel’s for further tone modification.

Posted on December 10th 2011 by

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