Noisy USB ports on desktop - what can I do?

[FIXXX]

Here's my setup:

Desktop computer with an Asus X370 Prime Pro - USB 2.0 Type B cable to an external audio card (Audinst HUD-MX1). The table has that fat coil-thingy.

That external card is connected to two powered monitor speakers (Mackie Mr5 Mk2) with proper RCA cables. The thick boys, not thin unshielded cheapo stuff.

- My issue is that the speakers make a super audible hiss when they're connected to the external audio card.

The fault is definitely the motherboard's USB slots because when I connect the card to a laptop - there's no noise whatsoever. 

Yes, I tried all the USB ports on the desktop.

Yes, the laptop was connected with a charging cable at the time of the test.

Yes, if I unplug the RCA from the speaker or the audio card - there's no noise anymore.

 

What can I do to clean that up? It's not a new problem, just supper annoyed that these great speakers are sitting here silent for several years.

 

[GuiltySpark_]

Something like this might work, however it's not solving the overall problem. 

 

https://www.amazon.com/Audio-iDefender3-0-Ground-Loop-Eliminator/dp/B01N3XKOLG

[FIXXX]

2 minutes ago, rickeo said:

Something like this might work, however it's not solving the overall problem. 

 

https://www.amazon.com/Audio-iDefender3-0-Ground-Loop-Eliminator/dp/B01N3XKOLG

That looks promising. May need to look up something similar in my country.

[FIXXX]

13 hours ago, Grumpy Old Man said:

must be nice to not be rubbish at proper electronics.

 

Update: asked on a local forum and a guy sold me his spare ADUM3160 B0505S 1500V USB to USB Voltage Isolator Module Support 12Mbps 1.5Mbps 

WORKS! whoopeee

[Psittac]

If this worked....... why isn't anyone selling it *in the audio space?  I know schiit had a decrapifier but I was told that they just integrated it into their dac's

 

*edit: oh that's sold by ifi audio, how the F have I never heard about this.  I asked a lot of people how to fix it and ended up going with a $300 galvanic solution (no physical connection)

[FIXXX]

3 hours ago, Psittac said:

If this worked....... why isn't anyone selling it *in the audio space?  I know schiit had a decrapifier but I was told that they just integrated it into their dac's

 

*edit: oh that's sold by ifi audio, how the F have I never heard about this.  I asked a lot of people how to fix it and ended up going with a $300 galvanic solution (no physical connection)

iFi's solution is $50. The Chinese no-name that does the same thing? … - 9$