Can a wah pot be replaced by an LFO?

[mth5044]

I was reading the article about adding an LFO w/ vactrol in place of a pot in a colorsound inductor less wah on beavis audio

http://www.beavisaudio.com/Projects/ColorsoundWah/index.htm

and was wondering if this could be done with the crybaby/vox type wahs? Since the crybaby/vox types have one side of the pot going to ground, I'm thinking it could but done, but I thought I'd see what you guys thought. I was also thinking about making it a triangle or sine wave to make it more luscious than choppy, but the LFO part isn't really the question here, just the replaceability by a vactrol or LDR. Thanks 

[Taylor]

RG has a schematic for a remote wah pedal retrofit for an inductor wah here. If you replace the voltage divider controlling the vactrol with the LFO, you'll have what you want.

[mth5044]

Awesome, thanks a lot Taylor!

[mth5044]

Alright, I get how to replace the wah pot with a photocell/LED combo (thanks Taylor), but I'm reading about so many LFO's I don't know what to do anymore.

Anybody know of a good LFO to use with a wah? (is this even done?)

I was going to use an auto-wah with the LED/LDR combo, so I figured I'd use an LFO to drive the LED also, for some fun, but I've been reading about the come up/down times for the LDR's. Sounds like this idea wouldn't hold up to well at faster speeds.

[Taylor]

The LFO from the Trumulus Lune is probably the most popular for grafting into other circuits.

Another new option is the TAPLFO from electricdruid.com. Even if you don't use the tap tempo option, this LFO is low parts count (when used with an LED/LDR) and incredibly versatile, moreso than any analog LFO I've seen. I don't think he's selling the chips individually, but if you can't program one and don't know how to get one, PM me.

LED/LDR combos do lose depth at very high speeds, but we're talking speeds right at the edge of audio (10-20 cycles per second). They hold up well at the sort of speeds that people usually use for fast tremolo, and if you don't want a choppy sound, even better, because they smooth out the response at higher speeds. There are other ways to do this kind of control, but they're all a lot more complicated.

Have you checked out the Gristleizer? It's an LFO-controlled bandpass filter, like a wah.

[B Tremblay]

Check out the Phozer: http://runoffgroove.com/phozer.html

[Processaurus]

I bet the weird waveform sequencer feature on the Molten Voltage LFO chip would sound really great driving an optical wah pedal.  That and sweeping the center frequency with the rocker pedal...

[Nasse]

I was  kid when I just hooked a ldr across my wah pot and made oscillator for pulsing lamp (reused a tremolo circuit). It worked quite well imho no other modifications in the wah circuit, super easy. We did not have leds back then I believe. I used bicycle or torchlight bulb and the circuit had a bias control so it has some kind of range adjustment. It was first time I smelled smoking potentiometer.

EDIT changed led>ldr in the first sentence and changed pot>potentiometer in the last. Just typos