> > I have the amp wired to the PSU via a molex connector and running off of 12V. > > Try running the amp off a separate power supply from the computer and see if that > helps.
Aren't sound card's notorious for picking up the noise inside of a pc? Of course I'm going from my memory of when PC Magazine talked about this issue with sound cards back when they use to print the magazine twice a month and had useful product reviews.