Midi over USB to Behringer synths not working (?)

Hi all. I am new to Metropolix and enjoying it so far.

I have a couple of Behringer synths - a 2600 and a CAT. I know I can easily sequence using cv-gate in the normal way from the Metropolix but I would like to drive the 2600 with midi sometimes, because the midi note value becomes a cv out in the bottom left (portamento) section of the 2600 and it is a handy control source.

Here’s the oddness: I know the Metropolix is sending midi out correctly via the expander, because I can see it in Ableton and the midi monitor. I also know that the Behringer synths are receiving correctly as they play when I send midi direct from somewhere else eg from the computer.

But: if I plug a cable direct from the Metropolix to the 2600 or CAT → it does not work.

I have tried a micro-B to USB-B (printer type) cable and also an adaptor that changes USB-A to USB-B. Neither is working.

Anyone else have similar problem?

Somebody discussed some similar issues on Modwiggler, and I could have this wrong, but I think maybe there’s something counter-intuitive about the way these things work that is at play, here. I think the intuitive understanding is “I’ve proven to myself that the Metropolix is sending MIDI and the Behringer is responding to received MIDI, so this should work” - the non-intuitive truth is that many USB devices (Metropolix included) need something to act as a host, and in the direct connection it’s not getting that.

I could be wrong! That’s my understanding via this thread…


As @neuromod mentioned, there’s a difference between USB clients (like the Metropolix interface, and the synths) and USB hosts (the computer). Connecting two clients together isn’t going to work.

Some USB implementations can be switched around (for instance, Deckard’s Dream can be switched to “host”) but it requires specific software and hardware support.

If you want to keep things in Eurorack, there’s the USB Bridge A from Tubbutec which does exactly what you’re hoping for between its two USB ports.