K1audio,
I checked my Sony BDP-S300 against another ordinary Sony CD player (I have four CD players) and it sounded identical when playing through coaxial digital out versus the other player on optical Toslink. No way I could tell which source was playing.
I have perfect level match as I used the same DACS....my DSP has Bur Brown OPA 2134 Op amp with AKM AK4382 24bit/192kHz DAC's of about 2002 vintage(nothing crazy fancy but good enough for me)....I use a APC H15 to power everything so I am not expecting any clocking issues or noise issues from power. I ran a test of identical music ( a burned copy of an original CD ) so I coudl flip back and forth hundreds of times from the listening position without moving my head...
BOTTOM LINE - NO DIFFERENCE.
As an engineer this is what I would expect from Sony or another reputable maufacturer but I may have tin ears - so be warned!
I could have conducted the test with Toslink ( as I have three Toslink inputs but they are all already in use) . Since I could not hear a difference in the first test I made I did not bother....