I bought this unit to use at my computer as a USB DAC / external sound card and struggled to get it going on my Windows 7 desktop. Not the Audio Alchemy's fault. Driver installation worked but when I tried to enable it I accidentally deleted.... in frustration I switched to the SPDIF port which is reported to give a much cleaner audio presentation. Foiled again. This time I needed drivers for my motherboard.
Long story short I decided to try it in my regular audio system and I was thrilled with the way it sounded! I don't have a digital streamer there so I cabled it up so that my CD Player fed its output to the Audio Alchemy. I have a pretty good system and it just made it come to life. Sweetness, clarity, musicality are just outstanding.
My system is centered around Quad ESL-63 electrostatic speakers and a tube amp, an Audiomat Prelude Reference MKII. My Quads were singing! Sorry, no test of the headphones, but I really like this DAC!