Thanks LA…nope, no H9 hardware, ‘just’ the original stomboxes 🙂
I’m afraid, that’s where I started – in the manual. Unfortunately, the stuff on page 20 just doesn’t work, BUT, if I partially pull out the expression pedal jack, it all works (green light next to effect flashes, parameter values change). The M Audio pedal is new, and this happens on all of the stompboxes, so it’s not a hardware error. Trouble is, I can’t even leave the jack partially out (obviously unsatisfactory in itself), as it’s a delicate balance for the jack to be in exactly the right place. This is why I think it has to do with something over the TRS designations (tho take your point, I was previously fiddling with something that related to an external switch). I’m baffled. The expression pedal is exactly the same, even down to the TRS jack, as the one Alan C plugs into one in the YouTube tutorial…aaagh!
But many thanks for trying to help, LA! Much appreciated! Best, David