Mark is correct to a degree. Some PC's create a lot of EM noise and the switching supply can create a lot of noise although not all of them are horrible. Still digital audio connections from PC's will sound better via optical connections most of the time or via a connection that eliminates the copper conductor connection that can cause ground loops. It varies from system to system. The closer your system is to the very highest end in sound quality the more these type of connections will rear there ugly head. Remember the noise conduct into the circuits that are dejittering and cause jitter. I find that the PLL system in the 518 does the best job at minimizing not eliminate this type of problem. FIFO just doesn't cut it when the jitter is bad. FIFO is good for that last ounce of detail but needs a clean stream to begin with. Something I discovered once with a 8 meter toslink cable that had a lot of jitter. A direct connection to a 568 and it was brittle and compressed sounding. Even Dolby Digital sounded like crap and DD is more robust from jitter problems. Feed the same cable through a 518 into a 568 and it was night and day better. Use a short optical cable for the best results from a PC if you go that route. I've run into these problems so I don't even consider them anymore. I agree with Mark.

Ron

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