Part Sony, part Accuphase.
The sixteen stereo digital-to-analogue ICs contained are Burr-Brown's 20Bit PCM-1702, while the drive itself is Sony's own G-Base also found in the Japan-only CDP-R3, the CDP-R1a drive and the contemporary CDP-X779ES & CDP-X707ES.
Along many hand-adjusted technical niceties, two 3-poles low-pass filters, optocouplers between sections, a highly linear digital volume control, fully balanced power-supplies and circuits (even the servo/controls' !) and outputs, the proverbial long-term Accuphase quality is provided.
However, as with any Compact Disc player, long-term means : "as long as the optical block does last".
I have no idea if Accuphase has kept a stock of spare blocks available for its older players. If not, a dead Accuphase player will only be... a dead Accuphase player.
Everything about it is available at Accuphase's own website.