Q#1)Why is it necessary to have a seperate processor when the Sony DVD SACD has decent quality DAC'S allready?
Sometimes DECENT just isnt good enough. Not to mention that seperate DACs that decode SACD/DVD-A as well as SACD/DVD-A players that put that signal out in the digital domain, are few and far between....Theta's Gen8 DAC does decode SACD, but thats the only one I know of. I read of a DVD player that puts out the digital signal but I cant remember for sure, I think it was a Phillips???? Slipknot1 explained the current situation well, but for reiterations sake, most DVD players (except the afformentioned Phillips??) ONLY put out an analog SACD/DVD-A output.
Q#2)Would it not be better to have a preamp that just controled volume and seletable source switching for audio and audio/video components?
BETTER is a POV question, for you I guess yes, for me no. I prefer my proccessing in one tidy box, except for CDs and I prefer my old Theta external DAC.
Q#3)Is the reason for a additinal processor for Dolby decoding for a VCR,satelite receiver or HDTV audio signal?
In general yes. Typically for the DD and/or DTS available from DVDs, plus a few surround matrix modes as well, of course only if desirable.
Q#4)If so,are there units that allow you to use the processor for just these functions?
Of course, an input, typically called a 5.1 analog bypass is used for SACD and DVD-A. Rotel, B & K, Krell, Integra, Sunfire, Bryston, and Classe, just to name a few, all make pre/pros that accept 5.1 analog inputs, plus a host of other user selectable modes. For the most part, most if not all, NEW pre/pros offer this input.
On your system you named a TV, an amp, a source, some speakers, a VCR, and a TV tuner.
1) Where is your volume knob currently located? As far as I know that source doesnt have a variable volume, e.g. Cary 308.
Thats the piece a pre/pro could/will replace.
(of course I did not mention the possibilty that you could use a preamp inline between the pre/pro and amp. But that brings up a host of new questions, such as, unity gain and theatre pass through. For these answers look at the threads named "PLease explain preamp theatre pass through," and "Seperating 2 channel and HT in the same system.")
I have just upgraded to a Bryston SP1.7 which has the 5.1 input, the Rotel RSP-976 I had also had these inputs. I have a Sony DVP-ns900v DVD/SACD and I am enjoying it, so my new pre/pro HAD to have this feature. The Rotel will probably be up for sale here, in a few days. Just in case your interested WINK WINK.