EB st volume pedal mods

[frobro808]

Is it possible???

Hey guys it's been a while since I've posted anything here. Hope all is well with you!

So to the point. I have a pigtronix envelope phaser II which was hooked up to two exp pedals. One side was your avg maudio pedal controlling the LFO speed for the phaser. The other side was an EB volume pedal that controlled the sweep of the filter. Great setup for an even better pedal!

Then I got greedy.... I decided what if I control both parameters with a single stereo volume pedal??? Went out the next day skipped to the store and grabb one... New. Bound home, hooked everything up aaaaand nothing. Complete failure. The speed control would work but not the sweep, ground loop noise etc. After some research I fi that it's meant only to be able to exp control from one 'channel' only (the 'b' or right side to be exact).

I was wondering if you gentlemen knew of any way I could rewire the dual gang potentiometer to bypass this limitation?

[ashcatlt]

You didn't say what this "stereo volume pedal" actual is, so we can only guess. Sight unseen, I'd have to say it's probably as simple as duplicating the wiring from the gang that does work. This might require replacing the jack with a stereo version.

OTOH - With most passive volume pedals (and expression pedal inputs...) you can actually use a TRS>Dual TS "insert" or "stereo split" cable to fake it. Plug the TRS end into the expression jack on the pedal you want to control, and plug the other ends into the input and output of the volume pedal. You have to check the documentation or measure with your meter to determine which goes where. There should be something like a +5V control voltage on either the T or the R - basically the "send" from the expression jack - that should go to the input of the Volume pedal. The other of T or R is the "return" voltage divided down by the pot, and should be plugged into the output of the V pedal. It actually should work the other way, too, but taper could be weird and at 0, you're shorting the +5V which could cause damage if that pedal is not sufficiently protected. The half of your stereo V pedal that does not work as an expression on its own might work this way without any rewiring at all.

[frobro808]

My apologies. It's an Ernie Ball 250k stereo volume pedal.
I have a mono version in which I use an insert cable and it works perfectly fine. However when I use the stereo version, it seems to only use half of the sweep (electronicly) even when engaging the full mechanical sweep.
Being the optimist I am, I made the best of the situation. I absolutely love the action of EB pedal hence the reason I did just get the pigtronix dual exp to begin with. When I look at the wiring (with untrained eyes) it looks identical so my guess is (again very uneducated) it's some kind of ground issue (mainly due to the God awful sounds it makes when attempting the dual expression). I'll try pictures of the guts when I get the chance. Thank you for the reply!