Here’s a Wah Wah I’ve built. It’s based around the old Vox Wah (How can you tell!?) but it’s got a few cool extras:
1) Input and output buffers so you can use it with all your stompboxes without it playing tricks on you.
2) Adjustable “Blend” control which allows you to blend in some clean signal with your Wah, this actually makes a real difference and allows you to wah wah away without completely Wahing out everything else you’re trying to do. It’s one of the best mods I’ve done to a Wah. You could in fact use the circuit I installed to run a “dry” signal FX loop which would then allow you to place more FX into the dry part of the blend circuit. Very cool but I haven’t yet done that – this is enough for now!
3) Standard cap, inductor and resistor tuning to suit your own tastes!