Okay there neck beard, I'll be sure to use obsolete TOSLINK cables, to connect my PC powered with it's "Plutonium 50+" efficiency rating PSU for the best results to "reject noise". Great advice... Please tell us more about all this digital noise rejection that's so problematic...
The free power supply that came with a $40 case that I spoke of has an efficiency rating of 60% and produces a considerable amount of noise
It is used only as a testbed for noise rejection of my DAC's over USB
Certainly optical connections will reject the noise unless the DACs power were suppied by the noisy computer in question
Noise is "generally" not problematic with quality brands of modern power supplies rated at bronze or above
I have never had a noise problem using a modern Corsair, EVGA or Seasonic of Bronze rating or above
I have many DACs that completely reject all noise from the test system over a USB connection even when using a 10 foot cable, and I have some DACs that do not reject the noise even over a short cable
For DAC's that do not reject all noise over USB, I use an optical toslink cable and a separate power supply that will not create a ground loop problem for the DAC
I never use a noisy test system for daily use
I only keep it for testing noise rejection of DAC's
How do YOU test for noise rejection?
By the way, Toslink cables are not obsolete!