Ground loop solutions, isolating amp power supply

Hardware
1

I’m trying to build some sort of portable synth and I’m powering all my devices using the same power supply, in my case a USB power bank:

  • The fabulous Zynthian
  • A PAM8406 based amp
  • A USB midi keyboard

As expected I’m facing the ground loop issues and I would like to solve them isolating the power source of the amp rather than adding an isolator or other filters to the sound signal. I think I would better sound quality this way, but please tell me if I’m wrong.

I would like to implement a solution similar the proposed in this video, using a Murata NKE0505SC, a 5V DC isolator (the amp uses 5V):

https://www.youtube.com/watch?v=b2Pb1KuVDS0

I tried powering the amp directly from the power bank, but as expected the ground loop issues persist.

However I’m having trouble sourcing the Murata NKE0505SC in Spain for a reasonable price. Has anyone built something similar or can recommend an alternative?

Thanks!

Here’s my current setup in all its glory:

8E9C8889-4D29-48F3-A7B3-14749A8D63CD
8E9C8889-4D29-48F3-A7B3-14749A8D63CD4032×3024 2.05 MB

zyn_portable_v1.mkv (2.7 MB)

2

I’m leaning towards finding an equivalent 5V isolator form another manufacturer that is easier and cheaper to source. However, in any case I should test if it will be enough for the amp as these isolators are rated for 1W.