Fast answer

Check the channel in normal OP-1 mode on the COM screen. Its default is channel 1; Shift + blue encoder changes it. Do not use the CTRL-mode channel control as though it were the normal-mode setting.

Try these checks

Open COM and select normal OP-1 mode.
Use Shift + blue encoder to check or change the MIDI channel.
Match the sending MIDI track to that channel and test a single note with an audible synth or drum sound selected.

Diagnose it

Are you changing the channel in CTRL rather than OP-1 mode?

Yes: Return to normal OP-1 mode and check its channel.

No: Match the sending track to the normal-mode channel.

What should happen

Matching USB MIDI notes can play the selected instrument in normal OP-1 mode.

Why this happens

Normal OP-1 and CTRL have different channel controls and different purposes.

If it still doesn’t work

Check the connections and settings described above. If your device behaves differently, email us with its model, firmware version and the steps you tried.

All OP-1 original fixes

References

Sources & review

Sources reviewed: 2026-10-03. Documentation does not replace a physical hardware test.

Original OP-1 — Tempo · Teenage Engineering · Original OP-1 online guide, chapter 10 · last checked 2026-10-03
Original OP-1 — Song rendering and connectivity · Teenage Engineering · Original OP-1 online guide, chapter 13 · last checked 2026-10-03

Sections reviewed: §13.2–13.4.