Originally Posted by reeseslover531
Tried that. No change :(
Separate power does not get rid of ground loop noise. If your DAC/amp and PC are all grounded (i.e. use 3-pronged plugs), you need your DAC/amp to have complete galvanic isolation from your PC to remove the ground loop noise, which means no electrical ground connection between them. USB, digital coaxial, and analog RCA all carry ground which will not help with ground loop noise. The only guaranteed way is to use optical S/PDIF, as the connection is optical with no electrical signal at all. This is the route I went for in trying to get rid of my ground loop problem, I bought an external DAC that had optical input, and used it to connect to my PC's optical out. I believe a USB isolator would work as well but I never used one (so I'm not sure if the one you linked is good or bad), as I wanted to upgrade my DAC anyway.
Of course if your DAC/amp is not grounded (i.e. use 2-pronged plugs) then you should not have ground loop noise, but this is rare as most DAC/amps I've seen are grounded. I tried this "fix" with my amp (bought a 3-prong to 2-prong cheater plug), and my humming was gone. This however is not recommended for long-term use as it makes potential malfunctions in your equipment very dangerous (if something shorts inside then the outer case could be carrying 110V socket power!).