Question Audio interference from ...motherboard?

[frank_packer]

Hi all,

Hoping for some assistance with a persistent interference issue I'm having with my PC audio set-up.
In running with a Schiit Modi-2 external USB DAC and Beringer Truth B2031 monitors. The monitors are on the same power outlet and the speaker cables are away from AC. The cables are RCA to unbalanced TRS.
I'm experiencing the interference sound linked below, but only when connected to the PC. It's not happening when connected to a different PC and it's not happening when the USB is unplugged, which leads me to believe that the source of the issue is the computer itself, not the cables or environment.
Before I start replacing motherboards and suchlike, has anyone experienced this issue? Any advice on solving it without gutting the whole PC?

https://www.dropbox.com/scl/fi/5eim...ence.m4a?rlkey=5dysta4opub44aau32zpozdsr&dl=0

 

[wmichaelb]

Hi all,

Hoping for some assistance with a persistent interference issue I'm having with my PC audio set-up.
In running with a Schiit Modi-2 external USB DAC and Beringer Truth B2031 monitors. The monitors are on the same power outlet and the speaker cables are away from AC. The cables are RCA to unbalancedTo isolate TRS.
I'm experiencing the interference sound linked below, but only when connected to the PC. It's not happening when connected to a different PC and it's not happening when the USB is unplugged, which leads me to believe that the source of the issue is the computer itself, not the cables or environment.
Before I start replacing motherboards and suchlike, has anyone experienced this issue? Any advice on solving it without gutting the whole PC?

https://www.dropbox.com/scl/fi/5eim...ence.m4a?rlkey=5dysta4opub44aau32zpozdsr&dl=0

I believe that you are correct, and the problem is with the PC. There are USB hubs designed to isolate DAC's and other equipment from such noise; one example is https://www.amazon.com/Nobsound-Audio-Eliminator-Industrial-Protection/dp/B07GF8643T. I have neither experience with this device, nor any financial interest in Nobsound, yada, yada, yada, but it looks like a relatively cheap experiment, and would certainly beat rebuilding the PC. Good luck, and let us know if you try this and it works.

 

[frank_packer]

I believe that you are correct, and the problem is with the PC. There are USB hubs designed to isolate DAC's and other equipment from such noise; one example is https://www.amazon.com/Nobsound-Audio-Eliminator-Industrial-Protection/dp/B07GF8643T. I have neither experience with this device, nor any financial interest in Nobsound, yada, yada, yada, but it looks like a relatively cheap experiment, and would certainly beat rebuilding the PC. Good luck, and let us know if you try this and it works.

Thank you for that suggestion.

I've since had a poke around with a multimeter and found that there appears to be an earthing problem with the PC. Connecting the multimeter to the metal chassis of the PC and the other terminal in the earth of a power outlet is showing a reading for resistance, which I believe should be zero in this instance.

Now I just have to work out what the next step is to find the source of the earthing issue...

 

[wmichaelb]

Hmm..do you have the noise problem with the other computer when it's plugged into this same mains socket? If true, then you have a home wiring problem. If not, I'd check the power supply first for good earthing.