by mcow » Wed Jun 29, 2011 11:55 am
I have a standalone audiophile DAC that takes S/PDIF, and I was feeding it with a USB=>S/PDIF box that had excellent specs and resulted in excellent sound (the Hagerman HagUSB). But I had to change that out because the USB signal level kept dropping in response to power events: the refrigerator in the next room would kick in and suddenly the DAC's circuit-protection relays would click and the sound would hiccup. The rest of the computer system never batted an eye: no noise on the screen, no other problems at all. It was driving me nuts. I never figured out exactly what the problem was but I became convinced that USB is just too fragile for a hi-fi audio output from a general-purpose computer. It adds too much software into the loop and, in my case at least, proved to be too susceptible to minor electrical noise.
Instead, I'm outputting to my mobo's Realtek and using the Realtek's digital output for S/PDIF into the DAC. This isn't flawless; I still get occasional short dropouts in the sound, but not enough to cause the DAC's relays to click, and much much less frequently than the problems I had before. I can't hear any difference between the Realtek and the HagUSB (which, per the manufacturer, has extremely low jitter).
I'm also using the Kernel Streaming plugin to handle the output. My DAC decodes HDCD and my FLACs of HDCD source material are detected as HDCD, which means I'm getting bit-perfect output.
Maybe if you had a small dedicated computer in the hi-fi that only ran a player, a disk, and a network connection, then USB would be OK. If I were searching for a DAC with more than S/PDIF, I'd be looking for one that takes IP (internet), i.e. DLNA; preferably wired ethernet. I suppose you could let it take WiFi but, in my environment, WiFi is too spotty.
(PM me if you'd like to buy my HagUSB.)