Massive hisses and electronic noises with using usb

Hey guys,

Using Hermod as an USB-Device is producing massiv hisses and electronic buzzes on the audio. I tried to change the places within the case, but it stays the same.

I am using a Doepfer P9-Case. Never had problems with it.

Any ideas what to do?


This is most likely a USB ground loop.
First thing you can try, is to power everything from the same power socket.

Hey joosep,

already did that. I am trying to use a Beatstep Pro with Hermod. Functionality is fine, but the Hisses and Noises stays.

I don’t have a Beatstep pro anymore, but I can assert that the Keystep is working great in the USB port. Midi, bi-directional, and no noise interference.

How are you connecting the CV and gate between Hermod and the BSP?
Are you just using USB/Midi?

Only USB so far. Nothing else.

And what is the noise coming from?

BSP and Hermod don’t make sound, so how are you connecting things?

1 Like

Problem solved. It was a common problem with Beatstep Pro. Groundloop. Beatstep is deliviering a extra cable to avoid that problem. I just forgot about that, as I didn’t use USB for a long time.

Fixed in seconds.

Sorry for the irritation und thanks for responding.


Awesome! Thank you for following up.

1 Like

Hello guys,

We found a software fix that will be in the next hermodOS version, soon to be released, improving a lot the noise amount!

To provide full transparency, we never experienced by ourself this problem with Hermod (unless with a cheap power supply) and according to users, it seems quite rare. But thanks to some users of this forum we were able to find and fix the issue.

We know that ground problems can be really tricky to troubleshoot. I take advantage of this message to list here some advices, helping you to reduce the noise of a module:

  • try to change the module position in your eurorack case
  • do not screw the module to see if it reduces the noise, or maybe use plastic screws
  • try an other 15V power supply adapter
  • try an other case (or an other 12V/-12V/5V power board)
  • try an other power outlet in your studio, without using outlet power strip
  • use a linear power supply (the best way to get rid of noises)
  • if the problem appears only when you use the USB HOST, use a special Y usb cable that power your usb device with a separated supply

Have a nice day, and stay safe!