I just bought a used Tracker Mini. I noticed that the MIDI over USB doesn’t work with the OP-Z or the EP-133, and I kind of expected that based on things people have posted. However, I can’t even get it to sync or trigger notes using MIDI in or out to these devices. Has anyone had success using MIDI sync/notes with the OP-Z or EP-133? I just want to know if I need to return this device because it has issues, or if it’s just not possible, like with USB-C.
Hey @deek311, welcome to backstage! 
This is an issue that i think was reported before. Check out this topic:
Hopefully you can find some answers there. I don’t have any TE devices so i can’t really help you, but from what i’ve read, it seems to be a bug and not an issue with the device itself.
I probably Should’ve said the 3.5 mm connections.
I was able to resolve the issue, somewhat. The reason the devices weren’t working is that I was using a standard TRS Type A cable, which is compatible with the OP-Z and EP-133, as it is a common TRS cable. However, the Tracker Mini requires a TRS Type B cable. The issue with the Octatrack was due to using a Type B cable that converted to Type A, instead of a Type B to Type B cable.
However, clock-in still doesn’t work properly! It only responds to transport in for syncing the clock. This feels like some kind of bug, because clock-in won’t work at all and the only way to record notes is to change between tracks constantly, but it doesn’t line up and only moves when a trigger happens.
I’m still puzzled as to why Polyend opted for Type B with a TRS connection. This decision causes unnecessary confusion, as most users are more familiar with Type A cables for 3.5mm connections. If someone wants to use Type B with TRS, they’ll likely need a converter, adding an extra step. Additionally, the MIDI clock isn’t functioning as expected. I’ve spent countless hours trying to resolve these issues, and Polyend customer service has yet to respond. It’s really disappointing—I thought this device would be a perfect fit, but unfortunately, it’s not.
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Ah. I thought we were only talking about USB MIDI. Could have told you about TRS-B from the get-go 
Glad you got it working though 
USB-C doesn’t work either for the EP-133, OP-1 Field, or OP-Z. It works for about 3 seconds on the OP-Z and then stops. I’m clueless as to why it works briefly. I might just sell the Tracker Mini because of these connection issues. For something so small and without a keyboard, it should be more friendly in this area. Maybe that’s why its value is dropping so quickly.
I had the same issue. I contacted support, and it took a week for someone named Martin to respond. He told me I didn’t need to convert to TRS-A and could connect MIDI to the OP-Z or EP-133 using a regular TRS cable without any problems. However, that was clearly incorrect. I can’t believe their support staff isn’t aware of these things. I’m in the same situation as you, trying to connect other devices without relying on multiple bulky converters, especially since the USB is only designed for desktop use (I mistakenly thought the OP-1 Field would work with USB-C). 
A portable device should offer more functionality in this area, and I haven’t used mine much because of it. I hope they address this in future updates.
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