Just making sure you’re not using the 9v and 12V jacks that are right next to each other on the 4×4? you have to pick one. from the manual: Note: The 9V and 12V outputs within a pair are not isolated from each other (their negative terminals are common). It is preferred to use only one from each pair. If using both, combined output should not exceed 400mA.
Thanks for the reminder. I’m pretty sure that I’m using the 12V on its own. I assume that the pair you’re talking about are the 9V and 12V @ 400 Ma and another 9V and 12V @ 400 Ma. I also tried using the included power supply for the H9 and the result is still the same.
I tried switching the midi connections from:
Musicomlab -> H9 Core -> H9 Max -> Timeline
Musicomlab -> H9 Core -> Timeline -> H9 Max
…and this seems to have solved the problem.
I will go with your suggestion and use a quad thru. I think it does make sense to have the midi signal sent parallel. Thanks!