How can I convert SPDIF to EFM (RF) signal, to use a cd player as a DAC ?

Hello

A friend of mine do have a kenwood DP-460 cd player with a dead laser, it was a very good sounding cd player, he ask me to modified this kenwood into a DAC.

So, to use a SPDIF signal, the only thing I should need to do should be to use a SPDIF to EFM (RF) signal convertor ?

I presume that the converted signal, after SPDIF to EFM (RF) convertion, should go to pin 29 of the TC9200AF data processor Ic ?

Any simple circuits suggestions for convertion of SPDIF to EFM (RF) signal and how to use it ?

Btw, using google, I can not find anywhere the data sheet for the TC9200AF and the TC9201AF, anyone do have them ?

Here is the part of the schematic of the kenwood DP-460 cd player.

Thank

Bye

Gaetan

[IMGDEAD]http://img101.imageshack.us/img101/4599/kenwooddp460smallfy3.jpg[/IMGDEAD]
 
No, a S/P DIF to RF converter is not how you would do it. You would use a S/P DIF reciever IC to convert S/P DIF to the digital format that the DAC IC (TD6709N) accepts. Everything before the TD6709N would be bypassed.

An IC like a CS8414 might work, but you would need to know what format(s) the TD6709N accepts, and to know that you need a datasheet.

Any way you go, it is going to take a lot of time and effort to do what you are proposing. I don't think it will be worth your time.
 
Looking over the schematic, there's not much there to salvage. The njm4558 are not very good op amps, and there's muting transistors in the signal path, I could go on. 95% of what's in the diagram would not be used. The only parts that would be reused are the DAC IC301 and the components in the lower right side corner of the diagram.

IMHO, almost anything you buy or build will sound better than this circuit as a DAC. Buy one of the DAC's from Brian at Twisted Pair or something else instead. By the time you build out the digital receiver circuit and it's associated parts, you will probably realize it's not worth the effort.

Someone in the trading post had an Adcom GDA700 for sale that will blow this CD player into the weeds.

I hope this does not sound harsh, but it's really not worth the effort - even for tinkering.

-David
 

gaetan8888

Member
2007-04-08 5:11 pm
amc184 said:
No, a S/P DIF to RF converter is not how you would do it. You would use a S/P DIF reciever IC to convert S/P DIF to the digital format that the DAC IC (TD6709N) accepts. Everything before the TD6709N would be bypassed.

An IC like a CS8414 might work, but you would need to know what format(s) the TD6709N accepts, and to know that you need a datasheet.

Any way you go, it is going to take a lot of time and effort to do what you are proposing. I don't think it will be worth your time.


Hello

Here is the only data sheet that I have for the TD6709.

With this data sheet can you find out the format(s) ?

Thank

Bye

Gaetan

[IMGDEAD]http://img142.imageshack.us/img142/6885/td6709smallwe2.jpg[/IMGDEAD]
 
Hello

Looking again at the schematic of this kenwood DP-460 cd player, it seem to be non-os with a kind of analog brick wall filter, L101, L201 and IC102 ?

Since I will not need to fix his Kenwood, I could use some parts, how about using this analog brick wall filter for a non-os dac (replacing the 4558 op amp by a better one and taking out the emphasis and mute transistors) ?

Thank

Gaetan
 
The format is described by the timing chart.

It looks like Right Justified Mode might work, but the chip would only accept 16 bit. Attempting to send anything else would result in static.

You could use CS8416 as an SPDIF reciever.

Personally, I think if you are going to go to this effort, you might as well grab a newer DAC - see what you can get from TI or Analog as a sample part :) The only downside is that these are all SSOP package parts, very small - but you could use a converter board used for prototyping to change them to DIP format.
 

gaetan8888

Member
2007-04-08 5:11 pm
jaycee said:
The format is described by the timing chart.

It looks like Right Justified Mode might work, but the chip would only accept 16 bit. Attempting to send anything else would result in static.

You could use CS8416 as an SPDIF reciever.

Personally, I think if you are going to go to this effort, you might as well grab a newer DAC - see what you can get from TI or Analog as a sample part :) The only downside is that these are all SSOP package parts, very small - but you could use a converter board used for prototyping to change them to DIP format.

Hello

Is it Standard Japanese input format ?

I have some DIR9001 receiver chip, can it work for it ?

Thank

Bye

Gaetan
 

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Looking at it, no... the nearest mode would be FMT1=FMT2=0, but the bits are clocked in the wrong way round and the LRCK is inverted to what the DAC requires.

It could be that TI and Toshiba use different meanings and it would actually work. You would need to invert LRCK from the reciever to feed it to the DAC, which is simple enough with a 74HC04 or similar.

I think if you are really keen, you need to try it. Make a small test board with just the DIR9001, and hook it to the CD player's board. Cut the traces to the DAC that bring in BCK, LRCK and DATA (pins 3, 7 and 8) and connect them to the outputs on the DIR9001. Remember LRCK would need to go via an inverter, or your channels would be swapped.
 
Hello Jaycee

I will try it, it is much for learning about digital, since if it not work I will wait for the PCM1792A that I did ordered and try to use it with the DIR9001 or the CS8414. That one would be for my friend since I would use for myself my TDA1541A chip in non-os.

Thank

Bye

Gaetan