ANSWERED!!: I'm currently using the CV output of My Helix to drive a relay input on my AMP. I measured the properties of the CV output and it delivers 0-5V at an output impedance of approx 660ohms. This is far too weak to drive a relay coil directly (which my AMP uses) so I've embedded a Field Effect Transistor (FET) into the body of the Jack plug inserted into the CV output socket of the Helix (I used a 2N7000 FET - cheap and easily obtainable).
The Gate of the FET connects to the CV output, the Drain connects to the AMP switching line, and the Source connects to ground.
I then set up a Helix footswitch (from the control centre on the Helix) to toggle the CV between 0 and 100. This drives the Gate of the FET and turns it ON and OFF (the Gate saturation voltage of the 2N7000 is around 2.1V). When on, the FET effectively shorts Drain to Source, so acts like a mechanical footswitch or relay contact, shorting the AMP switching line to ground.
