A Different Wah?

[zener]

I found a site http://members.shaw.ca/roma/wah.html where there's a wah that doesn't have an inductor but just two op amps and a led/ldr as the main parts. Does anyone build it already?

Anyone, what do ya think of it? Just an opinion or a mere impression of the design.

I always think that a wah pedal would be my toughest build. I'm having difficulties finding suitable inductors here and audio transformers are no guarantee that they would work. Before, I had my eye on the Anderton Antiwah but I read from here that it's more of an autowah. I stumbled on this site and found something nice (hopefully). :roll:

So, once again, what do you think of it just from the design only.

Thanks. :wink:

Zener

[R.G.]

You may want to read "The Technology of Wah Pedals" at GEO (http://www.geofex.com) for some background.

The circuit shown is a bridged-T active filter wah, very similar to the twin T filter in the article. It's a "resistor-to-ground" wah and uses the LDR for the variable resistor, as in some other variants, including Craig Anderton's "Clean up your wah pedal" article from Guitar Player a couple of decades ago.

It should work OK. There are other active filter style wah circuits, including the one mentioned in the GEO article. You can also use a state variable bandpass filter for this.