CPU Hum in Hermod

So I have been getting a very annoying and prominent buzz from Hermod since day one. The buzz changes in character whenever I press buttons or when I run the sequence. The hum exists whether or not I use USB and only goes away when I disconnect Hermod from my rack. I’m using a 4ms Row Power and a 90w power brick that Foundsound.com sold with the Row Power.
I have read another post about swapping out the power brick for a MeanWell one, but don’t want to spend $50 on a fix without more people chiming in to say this resolved their issue.

Are there any other solutions I could try first? Or is this new power brick a sure-fire solution and may as well give it a go?

Any help is appreciated at this stage.

I have the exact same issue with mine, when changing modes the LED’s or some other interference cause different pitch hum in my signal path.

I’ve tested it from a Doepfer LC9 that contains a Meanwell PSU 3 and a Make Noise powered skiff, and neither supply makes a difference.

The sound gets more prominent with a USB device plugged in. I have been told that a linear PSU would probably solve the issue but haven’t got one to test.

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!

I hope so as I had to remove Hermod from my Make Noise case because of noise.

I also really hope this update fixes some of the smaller bugs that have caused me to relegate Hermod back into it’s box and hovering in my Reverb draft list.

And who knows, maybe some new features… :see_no_evil:

I have an Hermod running just fine in a Make Noise Skiff. No issues. But, I do have issues with freezes when randomizing patterns that I’ve informed Squarp about.

Yes, that will also be fixed in the next update!