My Line 6 Toneport UX8 has an input for an expression pedal; I ordered an el-cheapo volume pedal (Behringer) online only to find it didn’t really work. Looks like the Line 6 box is expecting to be hooked to the ends of a 10K potentiometer, not to take a voltage input and compare it to a reference. (which IMO would have been a better scheme) Luckily I had an old Crybaby that hadn’t worked in years. I got a new pot for it, gutted the internals, and wired the pot to the output jack and the switch terminals to the input (for use as a footswitch controller). The only really tricky bit was that the pot mounting shaft wasn’t long enough and I stripped out the threads on the mounting nut. If racing motorcycles has taught me anything, it’s that any mechanical problem can be solved with a proper application of zipties.
Presto! After setting up the driver inputs, I can now control the virtual wah inside the Line 6 guitar amp module in Record (and record its values), and the on-off switch even works like it did back when it was analog. Rock on!