Regarding your DAC question: IMHO, you can do no better (perhaps at any price...) to use a Benchmark DAC1. This assumes you want "The Truth" from your digital sources, and not a colourized version. Accuracy is what the DAC1 is all about, and some compare and complain it's not quite "warm" enough... I think they're missing the added distortion in that frequency range produced by lesser products.
You may find the DAC1 USB version suits your computer-as-source configuration best - it's nice to dispense with the fuss of external pro/semi-pro soundcards, if you are only concerned about playback of 2-channel audio.
See http://www.benchmarkmedia.com/dac1/ for product details. But wait... There's More !
You'll find a (very long) thread at www.Head-Fi.org which is amazingly informative on DAC1 - it is blessed by the participation of one of Benchmark's engineers, who answers all manner of questions in very specific detail. I have never seen a manufacturer reveal such detailed information on the internal design of their product. Go to http://www.head-fi.org/forums/showthread.php?t=225363 and search for posts by EliasGwinn - after reading all about this unit, I think you'll want one !
The DAC1 USB can replace both your Headroom Cosmic pre-amp and M-Box... simplifying the setup and dramatically increasing the fidelity to your source files !
(BTW, I have no financial interest in Benchmark... I just love their gear for both home & professional use)
OK Gonglee3... there's my suggestion, I hope it helps. Grant
