billy p and MACCA350,
I have two DVD players, one of which I am using Solely as a cd player, and have them both connected to my receiver via coax. My Pioneer I also have connected via the analog 5.1 channel outs, for the SACD and DVD-A output. I believe that that is all that those are used for, correct me if I am wrong.
I have used Dolby Digital CD's, DTS cd's, HDCD CD's, and regular PCM CD's in both players, all over the digital coax out to the receiver. This works fine for me. Basically, the player is simply reading the signal and pushing it out unprocessed (if I understand this correctly that is) and the receiver is the one that does the sound processing and pushes it out over the speakers. That is why if your receiver can handle the DD, DTS, HDCD etc signals, that you can hear each of these formats.
If you want to try it out, burn some DTS and Dolby Digital wav files to a cd as an audio cd, and try it out. You should be able to see the DTS and DD led's on your receiver turn on. If you want some free wav files to mess with, here is where I found some:
http://www.sr.se/cgi-bin/mall/index.asp?ProgramID=2446
My favorites are:
The Run - Just a simple surround test of a guy running all over the place, the sounds are incredibly realistic, and it's actually quite funny the story that it tells, just with the sounds of footsteps.
There are four classical songs - Night on Bald Mountain by Mussorgski, Something from Strauss, and two from Mendelssohn, one of which is the Midsummer's night dream overture, I don't remember which ones the other two were... Anyway, they sound great!
The Saga - If this is the one I think it is, it is really very funny.
Here is an interesting site if you like trance like stuff, it wasn't my favorite, but was interesting to listen to for a few minutes and does a good job of showing off the DTS and DD CD playing ability of your player:
http://www.diatonis.com/downloads_dts_ac3.html
Let me know what you think.
-capT