I wonder if a 2 port USB power bank would let you send charge to both the OP and the polyend with the two splitter set up method?
Could also go in a different direction to take polyend USB midi out of the equation and use the TRS out:
I wonder if a 2 port USB power bank would let you send charge to both the OP and the polyend with the two splitter set up method?
Could also go in a different direction to take polyend USB midi out of the equation and use the TRS out: