how easywouldit be to ad a digital output to a cd player without one

[The Vinyl Adventure]

ok, you gonna have to be patient with me a bit here .. any answers need to take into account my completely basic electronics knowledge

ifthere was a cd player that i liked the look of on ebay that pre dated digital outputs as a standard would it be possible to just by pass the in built dac and conect it to an exterbal one... ... or does it not work ike that?

[The Grand Wazoo]

I'll be watching this one Hamish, because it's a question that's always been nagging away in the backof my mind.
If I used smileys, I'd have put the popcorn one here!!!!

[Stratmangler]

... ... or does it not work like that?

Sounds like a lot of work on something that's likely to turn its' toes up at the slightest provocation.

I'd suggest leaving the older players alone - it ain't worth the outlay.

Chris:)

[Themis]

ifthere was a cd player that i liked the look of on ebay that pre dated digital outputs as a standard would it be possible to just by pass the in built dac and conect it to an exterbal one... ... or does it not work ike that?
You need to put an S/PDIF output stage into an old player that doesn't have one ? That's the problem ?

[The Vinyl Adventure]

maybe im just being nieve, but surely there has to be somewhere on a pcb where the signal is the same as it would be as it exits from a coax output?

[Themis]

maybe im just being nieve, but surely there has to be somewhere on a pcb where the signal is the same as it would be as it exits from a coax output?
I'm not a specialist, but I don't think so. Internally the signal and the clock follow different paths afaik. Only an S/PDIF stage combines them into one. But I'll stop here, hoping that a specialist will explain better. :scratch:

[The Vinyl Adventure]

nothings ever bloody simple is it?! :)

[Themis]

nothings ever bloody simple is it?! :)
Well, it shouldn't be too difficult for a dac designer to do that, actually. Duncan should know how, perhaps ?

[The Vinyl Adventure]

For a numpty like me though ... ... ???

[Rare Bird]

Remember the old Mission DAD7000 player (Supercharged Philips 104)..That had it's DAC loose in the back encapsulated in resin, suppose that could be replaced if you know what you were doing.The trays in these were great..

[The Grand Wazoo]

Whoah!! That's too spooky!
The reason I've had this question banging away in the back of my noddle for nearly 20 years is because I've got on of those on long term loan to a mate & I always thought the chunkiness of the build must make it a good candidate for a transport to a modern DAC.

[Rare Bird]

I bought a Mission 7000 when they first came out,took me months to pay for it, had just left the record shop at the time to started my appreticeship in cabinet making..I think thats right..Cut a long story short it was on the tickker..

[Tom472]

I think the answer to the question is probably - "It depends"

Data inside CD players isn't shifted around in S/PDIF format, but there may possibly be the provision for it even if there isn't a digital out socket on the player. For example, on older Philips based players, the S/PDIF is supplied by the SAA7220 chip, which all of them have, but only some provide digital out. I could be wrong, but I think it's only 2 resistors plus a socket to make a digital out in that case.

But every player is different, getting a look at a service manual for your player of choice may shed some more light.

Regards
Tom

[leo]

Good reply above

Put simply it all depends on the cdp and dac
Some chip sets like the old Philips receiver SAA7220 inside some cdp's do offer s/pdif output pins which can be tapped into (it usually takes more than just running a wire from the pins) , s/pdif then gets sent to the external dacs own input receiver and then converted to a code the dac chip recognizes usually I2S based

Tapping into a chip inside the cdp and going I2S direct to the external dacs internal chip is also sometimes possible and can offer better performance , the downside is I2S isn't suited being ran over longish distances unlike S/pdif
You can add a buffer to the I2S but this may make things more complicated .

Also remember that a lot of the older players based around the Philips chip set tend to need the backside modding off them before they are good performers, just because its built like a brick s*** house does not guarantee it'll be a good performer as is, psu noise and jitter etc is probably poor