Voodoo Lab

Any known issues with using a Boss FV-500H as an expression pedal with the GC Pro?

I am trying to connect it up (using the Expression jack on the FV-500H and a TRS balanced 1/4 in cable), and am not getting right results.

I am trying to get it to control wah settings in a Line 6 Spider Valve mkII. I couldn't get that to work, so started trying to get it setup just to do volume, since that should be a more foolproof test.

I have P1 turned on in the global settings, and I have the expression pedal settings in the patch set for P1 to control MIDI CC=007, and I made sure the Spider Valve is the selected device. I verified 007 is the MIDI CC for volume in the Spider Valve.

I verified that the GCP is receiving signal from the FV-500H by making sure it cycles through the MIDI values 000-127. It does (although it reaches 127 before the pedal is fully "toe down")

But, it is not controlling the volume on the amp - it gives a "stuttering" kind of effect - almost like using a Les Paul toggle in "kill switch" mode with one pickup turn all the way down. There is no difference in volume between toe down and heel down.

I am going to verify my setup again tonight, as well as verifying my settings on the amp, but just wanted to see if there were already known issues.

Thanks!

The FV-500(H or L) should be fine with the Ground Control Pro. It sounds as if you are doing everything correctly on the Ground Control Pro programming and there are no known issues that would cause this.
Do you have any other way to send the Control Change data to the amp in order to confirm that the amp is functioning properly?

Thanks John. Right now, I do not have another MIDI expression pedal. I am trying to get hold of a Line 6 EX-1 and see if that will work through the GCP. If it doesn't work, and if I have the GCP setup properly, then I suppose it is an issue with the MIDI implementation on the amp (wouldn't surprise me - Line 6 puts some strange limitations on their MIDI implementations - either by design or by accident, I am not sure which...)

I doubt you will see any difference with another expression pedal. You say you can see the numbers sweep from 0-127 on the Ground Control Pro when you sweep the pedal... this means that the Ground Control Pro is successfully reading the pedal.