Author Topic: USB noise - cheap solution!  (Read 317 times)

Ilgrazza

  • Team member
  • *
  • Posts: 2
    • View Profile
USB noise - cheap solution!
« on: August 08, 2017, 09:26:37 PM »
Xavier

I love my PreenFM2.

I had a slight issue with ground loop noise when using usb power; this is reduced, but not eliminated when using the 9v PSU.  However, I found a cheap solution by accident - the noise disappears when the Preen is connected to the PC via an old KVM switch (£5 from Ebay).

Xavier

  • Administrator
  • Hero Member
  • *
  • Posts: 1281
    • View Profile
Re: USB noise - cheap solution!
« Reply #1 on: August 09, 2017, 10:58:49 AM »

Thanks for the info  :)

When you power with a PSU AND plug the USB to a computer, did you remove the JMP2 jumper ?

Removing the JMP2 will prevent using the power from the USB.
If you leave it you have current from both the PSU and the computer coming in the preenfm2 which must be avoided.

Xavier

Ilgrazza

  • Team member
  • *
  • Posts: 2
    • View Profile
Re: USB noise - cheap solution!
« Reply #2 on: August 13, 2017, 10:51:41 PM »
Xavier

Thank you, I didn't know that - my Preen was built for me.  I removed the jumper and the noise is fully eliminated.

Keep up the excellent work!

mzero

  • Team member
  • *
  • Posts: 8
    • View Profile
Re: USB noise - cheap solution!
« Reply #3 on: April 20, 2018, 06:26:11 AM »
Just leaving a note for others that might be searching up this topic:

This approach also worked for me: Remove Jmp2, then use the PSU for power, and USB just for MIDI - removes all the noise I was hearing on the audio outs when I was using just USB alone for both power and MIDI.

My unit is a van daal built unit, but it wasn't too hard to open it up and remove the jumper.