I was in the all amps sound the same camp until I got this one.
It hisses. The first one I got was refurbished and broken, the second works but there is blatant hiss on the speakers(not that audible), and on the headphones.
I tried connecting the headphones directly to the soundcard with a Y adapter since the m-audios have RCA outs, and there was no hiss, even at top volume, and did the same for a portable source. I tried a few different things, but still got hiss out of it.
For $193, I got what I paid for, but if I could go back in time I would have gotten a higher quality amp. Now, everytime I want to use my headphones, since they're shure in ear ones they really amplify the hiss so I have to take the rca cable to the receiver out every time I want to use them and plug the y cable with the headphones plugged to them into the soundcard. It's a real pain in the ass, and in the end, would have been worth spending more on a used or refurbished NAD. My old laptop, which had horrible integrated sound hissed but it was much less obvious.
Don't expect any insane leaps in quality though. Bigger bass, crisper treble, etc - blind tests have proven that even stuff like these HKs are pretty transparent. The only difference I've ever noticed among quality modern audio amplification is the power behind it, and how much it hisses(if at all).
