Byteme,
I have owned 2 different DVP-S7700's, one stock and the other "transport" mod'd by a well reviewed professional mod'r. I had hoped to use one of these with an external DAC and replace my expensive dedicated CD player.
Well, it just didn't work for me. With either a Birdland Odeon Lite or Channel Islands VDA-1, it did not sound as good as either of the dedicated CD player I had in house at that time (Theta Miles-Balanced version/Cary CD-308). When I switched to the Cary as the transport, everything improved. The soundstage was again wide and deep like when using the standalone CD player.
Now, I'm not saying that the Sony is a bad transport, it just didn't work for me. Many people have liked the Sony DVP-S7700 as transport or as a standalone CD player. But, for me, using the Cary as transport was easily, noticably better. So, my experiment did not produce the results that I had hoped for. I wanted to lower my overall cost and have a CD transport/external DAC and use the transport as my DVD player.
Ultimately, I ended up selling the DVP-S7700 and buying a Sony DVP-NS315 for $89 and having separate DVD player and dedicated CD player.
YMMV, just relaying my "perception" using my equipment in my room. I'm, uh, "frugal"!!! To spend more money is painful. Obviously, I think my perceptions are valid!
Enjoy,
TIC