[fonesgonewild]

Just curious that using the USB DACs with amps would improve the music quality over the soundcard mini out.

Some say that USB ones don't benefit as much, that just using amps directly from the soundcard can do better.

As I was searching, most of the head-fiers prefer to use the DACs with digital(coax/optical) inputs instead of the USB DACs.

I found some USB based Dacs from stereo-link.com, I thought they looked decent?

 

[AlexRoma]

I have a StereoLink DAC (Model 1610) in use for some time .
 
It sounds better then any sound-cards below 500$ I had previously used, including AudioGD NFB11 Dac-Amp (Sabre32). 
 
The signature is on the brighter side of nature, it reminds me those Asus Essence STX cards but with softer treble. XtremeMusic is a more neutral DAC, but it totally fails A/B competition at such stuff as dynamic range, fluidity and resolution.
 
DAC 1610 can be also described as clean, airy, extended. Dynamic range is great, it leaves a sense of huge extension. My previous NFB11 dac wasn't bad either, but here, the dynamic range is much better. 
 
I don't quite like the way it renders soundstage. It's a tipical delta-sigma way of presentation, as you could have listened an open-air concert at a stadium or summer camp. You don't get the sense of intimacy. It's hard to sense the size of a music hall or the architecture of the record studio with this presentation, but you never have the sense of compression or fake timber. The music is clear, airy, but not quite life-like articulated, because of USB jitter I suppose. But hey, I have never heard those  abilities among USB Delta-Sibma DACs at all, especially below 500$.. 
 
No connectivity/compatibility issue on Windows XP and Win7..
 
Highly Recommended in ~400$ price-range department.