My onboard soundcard produces hiss in my headphones (Sennheiser HD 202), and I want to use a USB soundcard instead, but I've run into a lot of confusion. I've found several devices that seem to do what I need, however they're labeled as amps, DACs or audio interfaces. Can those be used as...

I'm using a pair of Sennheiser HD202's, plugged into a Realtek HD soundcard, and I'm hearing a weird kind of static in my headphones whenever I do certain things on my computer, like scrolling down a page in the browser, or selecting text anywhere. That alone wouldn't annoy me so much, except...