Are you listening to the same music as you did in the store? You did mentioned noise when you turn up the volume on some tracks. That shouldn't be there, unless it's part of the original recording. Many hifi stores (at least here in Sweden) have a loaner system, so you can borrow demo cables and equipment and try them out first. If you're set on getting an expensive USB cable I'd try before I bought one, because it's possible it might not make any difference at all for you.
It might be that the store was using a cd player with a much better dac than the one in the HDVD 800. The HDVD 800 dac is great, but not as good as higher end separates. But if you're getting weird noise there might be something else going on.
It might be that the store was using a cd player with a much better dac than the one in the HDVD 800. The HDVD 800 dac is great, but not as good as higher end separates. But if you're getting weird noise there might be something else going on.