What am I missing using a 20 year old CD player??

Here's my point. I have no idea how good the Sonographe player is in question, or after 19 years if it is still operating up to spec. I do know that there have been clear improvements in clocks, filters and DACs used in CDPs since 1988 that all have the potential to improve sound quality, and that these developments have trickled down to less than state of the art machines. There are also corners cut in terms of other components inside electronics equipment that tend to offset the improvements in digital components of lower end machines compared with 20 years ago.

So, now we have machines available in and around $1000 with modern DACs, low jitter, and either upsampling (Cambridge 840C) or use other tricks (Rega Apollo) to get the most out of digitally recorded material. Worth a try to see if you can do better than what you currently have within your budget. If not, then be satisfied in the knowledge that what you have is still pretty darn good.

Jimbo, do you think you'll try some power conditioners before changing anything else?

Good point psacanli.

No point in investing in really good equipment without first assuring good power conditioning!

a better question might be:

"what am i missing using a current cd player" ?

both questions are rather ambiguous, or at best could be answered positively or negatively.

the idea is to audition cd players, comparing them to the sonographe. if a player is preferred over the sonographe and is deemed a good value, it would make sense to replace the sonographe.

I have many old cdp's, including the Sonographe SD-1 Beta. I opened it and found it totally similar to my Philips CD-350. It runs on CDM-2 pickup, and two TDA1540P DAC chips.

The similarity ends there, from which point onwards the SD-1 has a revamped output section that uses transistors, no operational amps (opamps) at all.

The output section can be upgraded with better output caps than the two huge German Era MKP 0.1 MFD/600V non-polar cap. I used a pair of T&T 10MFD/1000V, and, another time, I used two British TCC metal cans at 4 MFD/600V. Quite a big change, as the soundstage unfolds with more "presence" (read: higher end spectrum in 12K Hz upwards).

Better still, trash the output board, add a second transformer and install a pair of 12AU7 or 6CG7, or 6SN7 (12SN7 in SRPP typology.

This old CJ CDP can put up a good fight against newer CDP, such as the Marantz CD-94 Mk I. The CJ　SD-1 always sounds musical, except when it plays the loudest Telarc CD's. There, it will start to "shout" at the listener. But with an SRPP tube configuration replacing the custom CJ transistor output board, you can definitely take a Cambridge 840C with WM DAC, and hear wonders from a tubed SD-1 during any musical passages.

So I am saying, doing it reversibly, one will find the SD-1 more fun. Still, wait until you do blind A-B-C tests ......!