Finding digital output

if you can find the DAC and / or digital filter chip (if the DF is not integrated into the DAC chip itself), then there will be an I2S bus leading directly into the chip carrying the signals you want. Add your own DAC inside the player, or put a SPDIF transmitter chip like the CS8414 on there, and you've got a digital output!

Unfortunately, I don't know which DACs the sony player is using, or the particular details of the I2S data format they're using. So, you'll have to trace the analog path back from the RCA outputs to find the DACs, and go from there.
list of digital output pins on decoder chip

Open your player, find the decoder chip (usually labelled DSP or Decoder on the PCB. In a Sony machine, its name should be something like CXD2518, it should be rectangular with about 64 pins.
Then go

It is in Chinese, but the meaning of the table was clear to me. The column dotx will give the pin number of the digital output.

I am not sure if the digital output can be disabled by soft- or hardware on Sony decoders. For Philips, there is a pin that will override any software command.


Digital out

The actual URL is

There is a bit more than finding the pin. Are you going to use a voltage divider and do you know how to calculate the resistor values? Will the chip drive this or do you need a buffer? Do you know how to AC couple this circuit? Also you had better have excellent soldering skills as lifting a trace is too easiy on consumer electronic circuit boards.

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?