Audible noise using G6 as DAC?

I’ve recently switched from using my G6 as an all in one to using the G6 as a DAC fed by an RCA cable into the Asgard 3 input.

Unfortunately I seem to be getting audible noise from the G6 such as mouse movements and GPU noise.
This is most apparent between 0-10 oclock positions which then disappears until around the 3pm position again.

I have the G6 powered via USB on the PC which feeds from the line out RCA to the Asgard. A memeber suggested it was due to the mic connection, But with the mic totally out the equation, Noise is still there with only headphones connected. I do not get any noise just using the G6 on its own as AMP and DAC.

Edit (Update):

If I feed the G6 from a different wall outlet and use optical out from the PC, The noise isn’t audible any longer but doing so makes me lose the mic and other functions of the G6 obviously.
So I guess its either find another solution of different DAC and mic or revert to the G6 fully and consider returning the Asgard unfortunately.

I was going to say grounding related issue, but then saw this

in another thread.

I would put some isolator (sometimes called hum eleminiator) between G6 and Asgard.
ART DTI for example, or Behringer HD400 being a cheap variant.

Even with the mic totally out the picture with the headphones only connected, I still have the same noise.

I’ve just tried USB power only from a different socket and all appears good. no noise now. I think I’ll maybe give that iFi idefender+ a try.

Sorted! The iDefender done the trick perfectly. No noise on the mic and no noise even up full volume on the pot!