Not sure if you bought an inexpensive DAC yet, but the Parasound ZDAC is most defintely worth investigating. I have only had it a week or so, but it is a keeper. I always hate the "good for the money" qualifiers on gear, but this thing is stupidly good for what it sells for (there are definitely deals to be had for new ones). Let me know if you want a more detailed discussion about what I like about it.
I haven't settled on a choice yet. I've been interested in the Bifrost, and debating whether it would be better to use the USB interface or the S/PDIF with a good soundcard. Then the mind wandered to a used Benchmark DAC1.
I would be interesting to hear your impressions of the Parasound.
The things that impress me most about the ZDAC are how clean it is, i.e., no digital hash at all that I can hear, how nicely extended it is from top to bottom, and how much more of the recording I'm hearing than before. I hear more of the reverbs on vocals, tremolo and other effects on guitars, and even subtle lines from instruments I had not noticed in the past. I'm also getting more of a sense of the dynamic range on the recording, maybe because (again) it's just very quiet and clean. I have to add, it's not completely broken in yet, nor have I tried anything but the stock power cord and USB cables that came with the unit. Some have said it gets better with better cables. That'd be cool, too. Good luck.