I use to have a CDP302ES which was a very similar player.
The Digital Filter is a CX23034, DA Chip CX20152
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Paul Miller described the CX20152 in an issue of HiFi news & RR
<i>"These DACs is in fact as multiplexed dual channel device with independent shift registers, latch and counters for the 8LSBs and 8MSBs. Here, any of the 256 discrete amplitude levels (including 0) are switched on or off at a rate of 255 times within each sample period. The data stream therefore emerges as a PAM</i> (Pulse Amplitude Modulation) <i>wave prior to intergration, which is akin to a multi-level version of PDM, offering good differential linearity but incurring very high speed glitches
An external intergrator is required to maintain the DAC output voltage during the subsequent deglitching period, which means their is a direct relationship between the maximum sampling frequency and available clock frequency. In the event, a clock frequency as high 67.74 MHz is required to process 2-times over-sampled serial data input "</i>
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Internally the DAC is ECL, it was one of the first 2x Over-sampling players to be released.
Pretty amazing for a player built in 1985.
I have a service manual,

can scan the schematic if you need it?
Regards
James