I take the DIN out from that into the Midi IN on the back of my Intellijel 7U case with a uMidi and this lets the OP-1 be the master clock and the tape transport controls uMidi’s RUN output (goes high while tape is playing).
That still leaves the MIDI IN input on the hobbytronics thing open so maybe if Octatrack went in there, the OP-1 would pass it through as well?
This assumes you have MIDI DIN input on your Eurorack.
something that happens when the OP1 is synced to external clock and using the tape in loop mode: any drift in incoming MIDI clock will eventually accumulate because the OP1 “tape” loops to absolute positions, as in the loop in/out don’t change absolute position if the incoming tempo changes.
long story short, it works better when the OP1 is master clock and with firmware 225 it sends adequate-enough song position so as not to throw off pattern machines that understand some of it (Volca).
The output is too low to drive some modules, even my Tempi seems to miss a few beats here and there. One solution could be the Pico Input, it can amplify two separate signals so it would be possible to boost the click track and the mono output