15 years ago Robin Trower called me and said he was doing some gigs with Jack Bruce and asked "Would it be possible to have a wah wah in a regular box so that one could get that "fixed wah" sound by clicking on the pedal?" He's got the first one, I think I have the other one.
Recently Joe Satriani asked me for one, so I revisited the circuit adding a Volume Control, 3 selectable Range Modes (Wacked, Jimi, and Shaft) , a Pickup Compensator mini knob (humbucker guys rejoice!), and JFET input and output buffers. These buffers completely isolate the circuit from outside influence and are only in-play when the pedal is ON, giving it a much broader range of wah effect, interfacing with all types of PU's better, and working with any amp whether it be hi-gain or clean. Turns a Fender into a Vox, and allows infinite sustain with little or no Distortion.