I have a Sony DVP-NS999ES and Denon 5803 amp. The Sony manual says if my amp has 5.1 channel inputs the hook up the 5.1 posts on the back of the Sony the inputs on the amp. The Denon has the inputs, so I've got the interconnects run. The Sony manual also says if I want to use the Dolby Digital or DTS decoder on my amp, then run an optical cable from my Sony to the amp. I've got that done as well. My question is, what's the difference. When playing a SACD, does it use the 5.1 channels from my Sony to the amp or does it use the optical cable. Also, since I've set this Sony up, I've lost my rear channel when I play a DVD. Don't know why. When I play any DVD's the Denon is in EXT1 and will not play the rear channel. There is no longer any pink noise going to the rear channel when I'm in set up mode on the Denon. I have no clue as to why. Thanks for any help on these issues and questions.