Same for me, it is a 2015 unit.
Here is the TE support generic answer (which didn’t help)
"Thank you for your email. About the noise:
Please check the internal gain settings, eqs, and effects. Extreme gain, high eq and some effects does produce noise by themselves. Particularly check the main effects as they affect all sound. Press MIXER and then T3 to toggle main FX on and off.
A known noise when recording at high input gain is a noise related to power peaks when writing to memory. Turn down gain and raise the external signal for better s/n ratio.
For noise related to USB please try disabling USB charging. Press SHIFT+COM and then T4. Turn BLUE to toggle USB charging. Wait a few seconds. This will cancel the noise. (Your unit will still charge if turned off and connected, regardless of this setting.)
You can also try connecting your unit to a self powered USB hub, or using a physical ground loop isolator, such as http://www.radialeng.com/stagebugsb5.php or http://www.radialeng.com/trimtwo.php
If there still is noise then try to disconnect all your equipment and listen so you can isolate the source.
As a last resort you can try performing a factory reset:
- Backup your data.
- Turn OP-1 off.
- Disconnect USB.
- Wait three seconds.
- Press and HOLD the COM key on the OP-1 while turning the power on. This will take you to the “TE-Boot” screen.
- Now press 7.
If you need any additional info or assistance please just reply to this email. Thanks!"