Thanks so much, great suggestion.
I downloaded Midi Monitor for Mac. It looks to me like everything is fine from the OP-Z notes are triggering from the right track. The only issue I had (which explains the doubling of channels I got before) was that OP-Z track 14 was mapped to track 16 as well, so both tracks were firing in the MicroFreak when set to channel 16.
I still have the OP-Z set to only send midi and clock, not receive.
If I plug the MicroFreak into Midi Monitor then I get nothing if I play the keyboard or twiddle nobs. Doesn’t matter what sync settings I use.
So I’m left with two scenarios at the moment…
MF utility>sync>source = usb/auto : can’t stop a sequence on OP-Z, it plays automatically and pressing stop just resets it. With this the MF arpeggiator and sequencer seems to work.
MF utility>sync>source = midi : OP-Z starts and stops sequences, notes come through to the MF but if I switch on the arpeggiator/sequencer it makes no sound.
So my guess is either the OP-Z can’t help but listen back to the MicroFreak in some way, which it shouldn’t, or something is up with the MF.
Weird, and a bit disappointing. @Xander did you have anything like this?