Expression Controlled Wah Pedal

[Fuzz_Pi]

Well all a wah pedal is is a manually sweepable band pass filter, so really any exp. sweepable
filter pedal with a bandpass option should work.

Personally i think band pass filters sound like shit (too harsh), a manually sweepable low pass
filter is cooler, like the iron ether xerograph std and dlx

[Schlatte]

Summed up: guts of the wah in a pedal on the board, and the ability to control it via exp pedal?
At least thats what im getting out of it, but I may just be a bad reader.

That's what I took from it as well.

I just recently sold the guts of a crybaby to nieh for this very thing. You could put the wah in a box, with a pot for the sweep (like the treadle would do), and that could be used for cocked wah sounds by itself. Add the expression jack to the pot, and then you could wah wah that way with an expression pedal. Or if you had one of those Third Hand things that twists the knob its on, you wouldn't need the expression jack/pedal cause it'd do the same thing.

Maybe I didn't explain the best. I want a pedal that has an exp/cv control input to control a filter in a similar way a wah would work. Or in the case of the m5, wah modeling controlled off the board with an exp. pedal.

The actual pedal would be on my board.

So that won't work... If I were you, I would just get a wah pedal I like, rehouse it into a normal enclosure and instead of the wah-pot I'd use a digital potentiometer. Then you put in a little µController that reads the CV in via the ADC and controls the digital wah pot. You could even include some "wah modes" like reversed, pulsed, sweep, etc. via the µController (a small PIC or a little Atmega would do the job for around 5-10$).

[Rygot]

Summed up: guts of the wah in a pedal on the board, and the ability to control it via exp pedal?
At least thats what im getting out of it, but I may just be a bad reader.

That's what I took from it as well.

I just recently sold the guts of a crybaby to nieh for this very thing. You could put the wah in a box, with a pot for the sweep (like the treadle would do), and that could be used for cocked wah sounds by itself. Add the expression jack to the pot, and then you could wah wah that way with an expression pedal. Or if you had one of those Third Hand things that twists the knob its on, you wouldn't need the expression jack/pedal cause it'd do the same thing.

Maybe I didn't explain the best. I want a pedal that has an exp/cv control input to control a filter in a similar way a wah would work. Or in the case of the m5, wah modeling controlled off the board with an exp. pedal.

The actual pedal would be on my board.

So that won't work... If I were you, I would just get a wah pedal I like, rehouse it into a normal enclosure and instead of the wah-pot I'd use a digital potentiometer. Then you put in a little µController that reads the CV in via the ADC and controls the digital wah pot. You could even include some "wah modes" like reversed, pulsed, sweep, etc. via the µController (a small PIC or a little Atmega would do the job for around 5-10$).

Why wouldn't a wah circuit with an expression jack replacing the standard wah pot work?

It would essentially just be moving the pot to the expression pedal instead of mounting it on the enclosure...

the expression pedal would just be like a wah with no guts...yes?

I understand what you're saying with CV in...but a standard exp pedal with a pot doesn't need a controller.

[Schlatte]

Yeah, but you would need a expression pedal with the right pot value. And if you want to use it with CV or something like an Expressionator later on, it could get tricky again. So I think that using a µC is the most compatible way.

[Jero]

Yeah, but you would need a expression pedal with the right pot value. And if you want to use it with CV or something like an Expressionator later on, it could get tricky again. So I think that using a µC is the most compatible way.

Isn't that the case with all expression jacks...needing one with the right value? The wahs I've used have had 100k.

[Rygot]

Yeah i feel like 100k is the most common.

However, yes schlatte, if CV was a must for later on, a controller would be ideal.

[Schlatte]

Yeah, but you would need a expression pedal with the right pot value. And if you want to use it with CV or something like an Expressionator later on, it could get tricky again. So I think that using a µC is the most compatible way.

Isn't that the case with all expression jacks...needing one with the right value? The wahs I've used have had 100k.

well, it's not the case with all exp jacks. Some of them are using the exp pedals as voltage dividers and work with CV. So the only difference in range is if the exp pedal has a lin or a log pot.

Yeah i feel like 100k is the most common.

However, yes schlatte, if CV was a must for later on, a controller would be ideal.

And for the 100k wahs- the JH-1 Crybaby, for example ( ) has a 470k... as far as I know
Maybe I just like to work with µControllers and CV, so my arguments are kinda weak but it is surely easier to just put an exp jack in there instead of the wah pot and do it that way.

[Rygot]

Yeah, definitely depends on what value you need. So in that case, design or modify a wah circuit that is compatible with readily available exp. pedals.

And I'm not gonna deny that your argument is valid with the microcontrollers.
I have very limited experience with them, therefore I can't use em to my advantage.

[snipelfritz]

Ok, I don't think I'm understanding this. Couldn't you get a wah and put it off the board where the expression pedal would be and it would take up just as much space minus the main housing?

I'm certain its not what you're looking for, but another approach might be the Plutoneium Chi-Wah-Wah. Very small footprint all in one enclosure.
http://www.youtube.com/watch?v=VpzcvNqfSEc

[Schlatte]

Ok, I don't think I'm understanding this. Couldn't you get a wah and put it off the board where the expression pedal would be and it would take up just as much space minus the main housing?

Yeah, but you'd have to wire your signal chain to the wah... like guitar- pedalboard- wah- pedalboard- amp...
If you had an exp. controlled wah you'd wire it guitar- pedalboard, with the exp pedal off the board- amp.

[skullservant]

Plutoneium Chi-Wah-Wah looks neat! I don't think my big feet would be able to work it very efficiently though...

[Schlatte]

^Yeah, it looks pretty awesome! But 280 US-$ is a little bit overpriced, I think.

[skullservant]

Yeah, wow, didn't realize it would be that much.

[Ilikewater]

Compactotron?

[Chankgeez]

... like the iron ether xerograph std and dlx

Yeah, I think this might do it.