Expression pedal problems

[63fender]

I bought the mission sp1-l6h dual expression pedal to control my HX stomp that I control via the GCP. The pedal works when I plug it onto the stomp directly but, i can't get the gcp to interact with the pedal. I have p1 and 2 turned on, I got to the edit menu to set the commands for the expression and the GCP doesn't read the movement of the pedal at all. Im using stereo cables that I know work. Anyone have any advice here?

[Marlboro05]

Hi there,
The Mission pedal you have is specifically made for the HX Stomp, I’m not sure you’ll be able to get it to work with the GC Pro. If you make your own cable you’ll be able to.

The GC Pro uses expression from tip to ring, where is the SP1-L6 Rev B, uses tip to shield for expression and ring to shield for the switch. So to get this to work, you need to modify one end of a trs cable, the shield needs to be moved to the ring and the ring wire to shield. This should do the expression side. For the switch cable, you’ll need the shield to be swapped with the tip. Give this a go and see if it works.

I’ve got a MXR High Gain Volume pedal that I’ve taken the board out of and wired the potentiometer straight to a stereo output jack so I can use a trs cable instead of an insert cable.

I’ve not got a HX Stomp or a Mission pedal but from reading the manuals and just testing my pedal and cable, this looks like what you need to do.

Cheers