“How was that sound found” … The Wah – Part 1 of more…

The first wah pedal was created by Brad Plunkett at Warwick Electronics Inc./Thomas Organ Company in November 1966. This pedal is the original prototype made from a transistorized MRB (mid-range boost) potentiometer bread-boarded circuit and the housing of a Vox Continental Organ volume pedal. The concept, however, was not totally new. Country guitar virtuoso Chet Atkins had used a similar, self-designed device on his late 1950s recordings of “Hot Toddy” and “Slinkey”. 
The creation of the wah pedal was actually an accident which stemmed from the redesign of the Vox Super Beatle guitar amplifier in 1966. Warwick Electronics Inc./Thomas Organ Company had bought the Vox name due to the brand name’s popularity and association with the Beatles.

wah pedal blog

There are some pretty decent DIY mods that you can do to squeeze out some extra juice.  Here is a short list of some that can be performed fairly easily on many Vox and Crybaby models.  Remember, before attempting any of these, do your research, measure twice and cut once:


    If you have the chance to “AB” 2 identical wah’s, one with the true by-pass mod, and the other one stock, you will hear a healthy amount of tone suck.  Check the online sources for the how-to instructions and get your wah dialed in.  IMO, this should be done at the factory, but……

      “Vocal Mod”

      Replace the 33K resistor in parallel with the inductor with a 68K. This gives a more vocal quality to the wah. Some Vox Clyde McCoy wahs had 100K resistors here.

      “Gain and Bass Response”

      Replace the 470 ohm resistor (some have 390 or 510) at the emitter of Q1 with a lower value. This increases gain, which is useful if you’ve converted to true bypass. The bass response is also increased. Too low a value here may introduce some distortion and make the wah sound muddy. Try 270 – 330 ohms to start with.


      Replace the 1K5 resistor between the base of Q1 and the inductor 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. Most people refer to the 33K as the “Q” resistor, but this resistor also affects the Q.

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