Stereo wah?

[HeavyFog]

So a friend of mine asked me if i can help him finally achieve what he called the "ultimate wah pedal". The idea was to extend the range of the sweep further in both directions and to have it in stereo so he could send the high end sweep to one amp and the low end sweep to another, all without panning the signal to each amp while doing, so a crossover is out. I love this idea and iv'e been brainstorming about a few ways i could go about doing this. The best solution i came up with was to put two modified wah circuits (based on the crybaby) in one enclosure with the signal splitting at the input to both circuits. One circuit would be modified to extend further into the high end of the sweep while the other would extend into the lower end of the sweep. I'm having two big issues right now with it.

1: Finding a dual pot i can put in a crybaby chassis may as well be completely impossible. I did notice on small bear they sell a pinion gear for knurled shaft pots but i'm not sure if using a regular pot as a wah pot would last that long. Perhaps i could modify a dual pot with a solid shaft pot to fit a gear with a D shaped hole? There's also the Ernie ball stereo pan 500k pot which would work, but i'm not sure if i could even mount it or not, plus i might not be able to get a gear onto it.

2: I know i can't just take one circuit and extend the sweep both up and down but theoretically it should be possible to extend the sweep further in an opposite direction for each of the two circuits (i think). Would that be possible?

Maybe there's even another, better way of doing it that i'm unaware of. Any ideas?

[digi2t]

1: Finding a dual pot i can put in a crybaby chassis may as well be completely impossible. I did notice on small bear they sell a pinion gear for knurled shaft pots but i'm not sure if using a regular pot as a wah pot would last that long. Perhaps i could modify a dual pot with a solid shaft pot to fit a gear with a D shaped hole? There's also the Ernie ball stereo pan 500k pot which would work, but i'm not sure if i could even mount it or not, plus i might not be able to get a gear onto it.

Not impossible. You just need to sit down and research the problem. You CAN fit a dual gang pot into a Crybaby. Either an OMEG, with which you'll have to shave down the casting a bit;



Or, a larger, heavy duty PEC unit, but you'll have to mod the casing to get it in;





As for the pinion gear, the "D" shaft model is what I use. Cut the shaft so it's 3/16" longer than the gear, file a flat on to the shaft, and slip it on. DO NOT file the flat all the way to the shaft bushing, leave yourself a 1/16" space here, and with a Dremel and thin cutoff disc, score the end of the shaft, flush with the end of the gear, and slip on the circlip. Bob's you uncle.

2: I know i can't just take one circuit and extend the sweep both up and down but theoretically it should be possible to extend the sweep further in an opposite direction for each of the two circuits (i think). Would that be possible?

Mechanically speaking, you can increase the sweep of the pedal by trimming the rubber bumpers. On the heel end, you can cut them down a fair bit, leaving just enough to preven metal to metal contact. The toe end is a bit trickier. You want to cut them down enough to gain more sweep, but not so much that you won't have any buffer left for switching the effect on/off. When trimming the toe bumpers, it's a delicate dance of shaving a little off the bumpers, readjusting the bypass switch, and trying it. You'll go back and forth a few times, but if you're careful, take your time, you can maximize the sweep here.

Finally, the real pisser in the Corn Flakes is that you won't find a dual gang pot with a sweep specifically meant for a wah. The best you get is a log taper, which will work, but will require getting used to where the knee of the sweep is. You might have to fool around with tapering resistors on linear pots instead, as done on the Ludwig Phase II, or Korg Mr. Multi.

Or....

Use a Morley casing, and convert everything to optical. Use two LED/LDR's, and create your own blind, as was done with the EH Talking Pedal clone.

[stallik]

I'm wondering. If you were to split the frequencies so that the highs and lows can be routed to different amps, would you actually need to increase the range of the wah? You could turn up the treble on one amp, the bass on the other and have something that's easily tunable per venue.

[Fender3D]

...or you may use something like EH bassball:
two filters, one going to left the other to right, and one CV...

[duck_arse]

gears. they mesh. might be possible to fit a standard pot and gear on the opposite side, and meshing with the original pot and its gear. might be too much backlash, might not fit, either.

[digi2t]

gears. they mesh. might be possible to fit a standard pot and gear on the opposite side, and meshing with the original pot and its gear. might be too much backlash, might not fit, either.

Ah... the Mold Spore angle. Yup, that would need a bit of metalwork, but definitely do-able. Get three rack gears and epoxy them together. Viva la DIY!! 




Wasn't Joe Gagan doing some kind of dual pot kit for the old stereo fuzz wah pedals a while back?




Gagan....

Gagan....

Gagan.... anyone?

[HeavyFog]

Thanks for the advice! I think what il do is use either an omeg or pec pot and modify it for the gear.

As for extending the range perhaps i could add resistance to either side of the pot? The goal is to extend the range of one end a bit deeper into the bass side, and the other a bit more into the treble side, so i don't mind losing some of the high end range on one side if it means i can do the opposite for the other.

Edit: just realised that the sweep cap off the emitter of the second transistor is responsible for the sweep position. In theory if I adjust that I should get the sweep lower?