Hi Sorry to reply so late I did not see your post before..
may be it's still time.
I do not know exactly what you are looking for as you have the answers it seems...
You are right, the DAC is the Sony CDXA 8042S
It just does the D/A conversion
the MDS-JA333ES has 2 DACs one for the left and one for the right channel. Without these there would be no analog output... the same as in the CDP-XA50ES by the way.
The chip are the IC nr. respectively 505 for the left and 503 for the right channel on the DA board. But I guess you found it...
I have a JA-3ES and a JA-333ES. For me the JA-333ES has a better sound and is capable of LP2 LP4 recording and playing and handles 48kHz/24bit digital signals.
I can not compare with the JA20ES since I don't have it nor with the XA20ES I have the XA30ES (!).
I'm electronics engineer, and as I could see there a not more than 2 DACs in the CDP players or MD palyers.(2 in fact. one per channel to avoid cross talk).
Hoe this helps.
BR, N.
