How to build a Digital input ( create DAC ) on a Technics SL-P999 CD Player

hello
someone already did this job on this forum with philips CD4000

so I would like to make my high-end CD player Technics model: SL-P999 work as a DAC.
so I would like to install an optical input.
because the sound of this cd player is phenomenally fantastic.
it says on it that it should be 20 Bits, now I don't know how much that is. I know, I know electronics, but not too much.. I know how to solder wires and work with a multimeter. but I'm a complete zero in this project. haha
i know i need a board most likely SPDIF to I2S.
would it be possible to connect this thing to my technics cd player.
 
Nooo. Where ??
it only has an optical output. look at the pictures
 

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Right, I'm going to hazard a guess and suggest that you need to break into the large IC chip shown in red square. This will be a sample rate converter that processes data to the DAC chips. Nice DAC chips by the way - PCM56P, however these are 16 bit DACs not sure why 20bit is needed.

It will be a bit tricky, full removal of PCB and carefully study the datasheet for the IC indicated, I suggest you run wires to the I2S data pins under the board, should be 4 wires usually. Not too much heat on those pins, decent iron and solder with lead needed.

Does this need to be switched? It will be always on if connected to the converter chip

Upgrade the entire PSU while you're there 😉


dc999.jpg
 
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hmm I don't quite understand myself. are you saying that the chip will have to be removed from the circuit? how will it work if you accidentally press play? while listening to external digital input. should I just disconnect the cd unit away...
 
No chip stays in PCB but you probably need to run wires from spdif input module to the chip, remove the whole PCB and run wires underneath to be tidy.

Sorry did you only want this as a DAC not as CD player? Then remove CD connector and send in I2S signal via the PCB connector.

Basically the only button needed on the front is the on button? all the rest are for CD access, you could remove the whole PCB and put it into a nice enclosure with better PSU.