MIDI "hangs" and freezes on external PSU?

#1

Hey guys,

I'm using my Ax as a multi-fx device for my Octatrack. I have a few objects with effects, and thought hey: why not use a spare Octatrack MIDI track to send CC data, thus controlling the Ax fx!

Problem is, once the patch is saved to internal flash and I boot it up using an external PSU the MIDi "chokes" out after a few MIDI messages. E.g. a few CC moves are made (manually) on the Ot, sent to the Ax, and then it stops responding. The MIDI LED indicator on the Ax stops flashing as well.

It works perfectly when connected to my computer via USB, but chokes out every time using and external PSU. I've used the following PSU's, all with centre pos:
9v, 3A
9v, 500mA
12v, 2A
12v, 3A

Any ideas here?

#2

how exactly is midi wired in standalone mode? could a midi loop be the issue?

#3

Hmm I hadn't thought of that but it's wired the same - the only difference would be severing the USB>Computer connection.

I might try fiddle with the MIDI thru settings (I have a few thru's going on) to see if that's the issue.

#4

Is the Octatrack also being run from an external power supply? Is the computer connected to the mains or is it a laptop?

Can you try it with both USB and external power supply connected to the Axoloti simultaneously. The Axoloti will take power from the external supply, but I'm thinking that the problem might be something to do with grounding, which the USB is providing via the USB cable from the computer (if that's also connected to the mains). With a laptop and external power supplies, there is no connection to ground through the cables - occasionally this can be the problem.