Who makes a pre/pro with SACD Input?

I have a Sony DVP-NS999ES DVD SACD player that I recently tried to hook up to my just purchased used Parasound P/DD 1550 and P/SP-1500 preamp/processor with Parasound FM tunner.After being told by the seller that I would need to purchase a $150.00 adapter cable and would then be able to use the SACD portion of the Sony unit I found out differently.When hooked up I had no volume control.Useless for practical puposes.I realize this is my fault! Incidently the Parasound units are now for sale for someone that wants to have a system without SACD.
My questions are these:
1)Why is it necessary to have a seperate processor when the Sony DVD SACD has decent quality DAC'S allready?
2)Would it not be better to have a preamp that just controled volume and seletable source switching for audio and audio/video components?
3)Is the reason for a additinal processor for Dolby decoding for a VCR,satelite receiver or HDTV audio signal?
4)If so,are there units that allow you to use the processor for just these functions?
My system consist of a Sony 36" HDTV ready monitor,the Sony DVP-NS999ES,a Nakamichi PA-1 high current 100 watt per channel 5 channel amp,RBH Sound 1266SE's full range towers for LR main ,a RBH 661SE center(goes down to 35Htz),RBH 61SE's for LR and RR(goes down to 45Htz) and a RBH 350 watt 1010SEP sub,a JVC Svideo VCR,a RCA HDTV receiver.
A pre/processor with 5.1 capability that is very clean and non-coloring is what I think I am looking for? Additional sound field processing is not necessary.
Any help would be greatly appreciated.Thank You in advance,
Steve