Wah wah into auto wah?

[BillyJ]

Isn't there a simple way to do this?
I could have sworn I have seen this a bunch of times but of course can find nothing now.
Isn't it a matter of replacing the wah pot with an led/ldr combo and using the variable resistance in place of the pot?\
If so my biggest question is how are the LEDS driven??

[R.G.]

As far as it goes, yes, that's correct. You have to drive the LED with a current that is proportional to the instantaneous loudness of the signal, so you have to add something to derive that. Generally this is all by itself as complex as the wah circuit, being either 2-3 transistors or an opamp with the surrounding RCs in any case.

[BillyJ]

RG can I ask what name these circuits go by?
I guess the build sounds a little more complex than I had hoped but I have a larger breadboard and I think I might rather enjoy the build.
Wah circuits seem simle enouh that if the LED/LDR part is comparable I'd like to give it a go.
Any other shoves in the right directions apprciated.

[Transmogrifox]

Send me an email transmogrifox@yahoo.com and I'll hook you up with some schematics that you may find helpful

[mattv]

If you want one that wahs when you pick a note, look at the Technology of Envelope Controlled Filters at Mark Hammer's site or Geofex.