Voodoo Lab

I am using the aforementioned in the subject line. On the EP11, I have the treadle/pedal jack connected to Pedal 1 input of the GCP and then the under treadle toe toggle off/on switch connected to Pedal 2 input of the GCP. I have enabled (set to ON) both pedals under the GCP Setup/Pedal menu. In a given GCP preset I configured Pedal 1 for CTL007 (Volume for Eleven Rack) and then Pedal 2 which is the EP11 toe switch configured for CTL043 (Wah Off/On for ER). Switch on EP11 (that is under treadle) is set to position to work with GCP.

While editing the Pedal section of a given GCP preset for Pedal 2 and watching the Current Value being sent by the EP11 ( 000 - 127 ) , when I press toe down on the EP11 and engage the switch repeatedly I observe the GCP Current Value go from 000 directly to 127 and vice versa). Weird thing is, when the EP11 toe switch is on / sets the GCP to 127, if I then move the treadle, the Current Value displayed on the GCP sweeps up and down between (0 and 127) as if it was volume pedal. If I disable Pedal 1/remove CTL007/set it to OFF in the GCP preset and repeating the process above, moving the pedal still causes the Current Value displayed on the GCP for Pedal 2 to sweep from 000 to 127. If I then disconnect the EP11 cable going to GCP Pedal 1 input jack, it works as I would expect. When engaging the EP11 toe switch the GCP Current Value for Pedal 2 goes from 000 directly to 127 and back and moving the pedal does not change the value.

So how is that if Pedal 1 is set to off in a GCP preset (while the Pedal 1 input of GCP is connected to treadle/pedal out of my EP11 pedal) that moving the treadle sweeps the Current Value from 000 to 127 for GCP Pedal 2 input?

Is this by design or is this a bug that can be fixed?

Thanks

This is both "by design" and can be fixed...

I believe you simply have to flip the Mode Switch under the treadle on the EP-11 in order for it to function properly with the Ground Control Pro. What you are seeing is the result of one of the "expression pedals" being connected backwards... the Mode Switch should reverse this backwards connection and keep the treadle and switch functioning independently.

I will try flipping the EP11 under treadle switch tonight and see what that does. What's interesting about this is the footswitch under the toe on the EP11 is simply an optional switch kit that I installed in the pedal. And it is fully independent and not wired to the treadle potentiometer. They are both completely separate/independent of each other. So what I have essentially in the EP11 is an independent instant access toe switch wired to it's own 1/4" jack and a treadle potentiometer wired to it's own 1'4" jack.
Thanks!

The only time one expression pedal port is affected by the other expression pedal port is when one or both of the devices using these ports is connected backward. This makes the expression pedals do strange things because you are essentially making one port swing the ground reference around for the other port.

The EP-11 does need the Mode Switch flipped to the opposite setting when used with the Ground Control Pro vs. using it directly connected to an Eleven Rack... so this could be all that is wrong, or it could be the switch that is wrong... or both could be wrong... Basically try swapping the Tip and Ring connection on ONE of these at a time then test. A maximum of three "swap and test" sessions will yield two independently working expression pedals.

For clarification: for the treadle to work correctly let's say connected to Pedal 1 Jack on GCP, it should be wired so that when I move the treadle, the Current Value sweeps from 000 to 127?

And then I would need to swap the tip/ring wires on the jack on the EP11 for the under toe EP11 switch until when observing the Current Value for Pedal 2 the value does not sweep?

A pedal that is backward may still show a full 0 - 127 sweep... so that is not necessarily a full proof test. It certainly works with something that does not yield the full range, but seeing the full range sweep doesn't always mean things are connected properly. Only seeing no cross talk between the two expression pedals is full proof that all is connected properly.

Right now we don't know if one or both of your "expression pedals" is connected backward but given the observed behavior... something is certainly backward. The easiest way to fix this would be to swap the connections on one, then test. If it still shows this cross talk, swap the connections on the other one and test... if it still shows the crosstalk then re-swap the first one and all should be fine... that's what I mean about the total of three "swap and test" sessions. Of course, at any swap and test session where the cross talk disappears means you are done.

I hope that clears things up an bit.

Will test it out.
Thanks for your time and help!

Flipped the switch under the treadle and it works fine now.
Thanks!