Wah Pedal Design for DJ

[robertolubongo]

Hey guys,

I've been tinkering with guitar effects on and off for years now, although not a lot lately.

A lot of my friends are DJs and I was hoping to make a box for them. What I was hoping to do was make a wah pedal box that could be used by a DJ - basically sit with his decks and then be controlled by a slider and a bypass switch.

I was wondering what design modifications I would have to make to a standard wah circuit (Crybaby, Vox, etc) to make it compatible with a DJ setup. The wah box would probably be in-line after the tables/mixer/preamp and before the main amplifier. Therefore I'm guessing the input levels would be higher than that of electric guitars, so modifying the input circuit would be necessary.

I'm thinking you would need to modify the 68k resistor in this circuit, and maybe change the control pot rating? :

The Technology of Wah Pedals

As well, I figure I might have to do some impedance matching and/or buffering, but am not really sure the best way to do this or measure the values I would need. It has been suggested I bump the supply voltage up to 12V-18V to deal with the higher input signal level. As well, I think I may need to do 2 circuits, one for each channel. If I combine a stereo signal into one line (mono) and use one circuit, would it basically sound the same at the output as a stereo signal that was modified identically in both channels?

Any input on this would be great, thanks.

[Steve Conner]

Allen & Heath already make a DJ mixer with voltage-controlled filters in it, that amounts to the same thing. You could just persuade your friends to buy those...

I seem to remember that Mixmaster Mike would take an ordinary guitar wah-wah, plug it into the FX loop on his mixer, and operate it with his foot while scratching.

Combining a stereo signal into mono before wah-wahing it won't sound the same since you lose the stereo information, but I don't see that being a problem.

With VCFs, you can gang as many of them as you want without needing a huge multi-gang pot. The Allen & Heath mixers have four filters, and you can have their CVs controlled by the crossfader, so you can filter one track in while filtering the other out. It's really nice. You couldn't do that with wah-wah pedals unless you were DJ Octopus.