Hi h317,
Luxman gear was very nicely designed; in fact, Axiom's chief electronics engineer designed amplifiers for Luxman back then.
The D/A converters these days are likely more linear, although even back in the early days of CD, low-level linearity errors were only measurable with test gear, as they tended to occur at residual noise levels 80 dB or more below reference level. Which is another way of saying I'd be surprised if you heard any difference at all between the Sony DVD player and your 18-year-old Luxman with music playback in a controlled comparison. To do that test, you'd need to connect both players, have duplicate CDs synched and running with volume levels identical, then switch between the two players and see if you can detect any difference.
Playing a disc in one player then moving it to the other doesn't count. Such comparisons are hopelessly uncontrolled.
Regards,
