TDA1541 DEM reclocking

[Sandor]

You can:
1) use a separate 11.289 MHz clock generator as the ones from Guido Tent or Elso Kwak (search this forum)
2) pick the clock from pin 19 (master clock) of the CS8412, if you use such a receiver IC.
Please share you experience with the DEM circuit.
Best regards.

Paul

[DragonMaster]

I still haven't started my TDA1541A project.

For now I'm going to stick with EIAJ as I don't have any other sources. Can I get this clock signal from a CDP? I don't know the controller chip for one if the CDPs but one is using CXD2500.

What I'm planning is:
- Pedja's DAC scheme with TNT1541 PSUs
- cm's EIAJ to I2S converter
- Pass D1 I/V stage
- DEM circuit

A KC will replace the one in the CDP

Future things I might add :
- PCM2706 USB to I2S
- CS8414 SPDIF to I2S

[DragonMaster]

1) use a separate 11.289 MHz clock generator as the ones from Guido Tent or Elso Kwak (search this forum)

It's not going to be in-sync with the CDP tho. Does it matter?

[guido]

If you mean that the dac and the cd player have a different clock:
yes it matters! they will not have exactly the same clock value, so one will be faster than the other. You will run into timing problems.

Without a 8414 reciever in the correct mode this will not work (and in this mode you will loose/double samples, depending on who's faster). But then you're stuck to spdif.

If you mean that the dac/player and dem reclocking have a different clock: yes it should matter: dem reclocking is to get the dem freq a multiple of the samplefreq (which is determined by the clock). If it is a different clock, this will not be the case (though better than the original dem oscillator freq i guess).

[DragonMaster]

Hi guido, so you're telling that feeding the DEM circuit with an other XTAL is not a good idea. Now the problem (At least for me) is to convert 33.8688MHz or 16.9344(I have the choice between both) to 11.2896.

[rbroer]

Originally posted by DragonMaster
Hi guido, so you're telling that feeding the DEM circuit with an other XTAL is not a good idea. Now the problem (At least for me) is to convert 33.8688MHz or 16.9344(I have the choice between both) to 11.2896.

Nope, you don't need 11.2896 neccesarely.
If you're gonna run your TDA1541 non oversampled, and you only got 384*Fs or 768*Fs available,
you can just divide by 64/128 resp. to get a DEM frequency of 6*Fs.
This will do the job just fine.

[DragonMaster]

And how can I get it to be NON-OS?

[rfbrw]

Originally posted by DragonMaster
And how can I get it to be NON-OS?

By not adding an oversampling filter.

[DragonMaster]

The chip is doing it by itself but apart from TNT's solution that requires either the 11.2896 or a CS8414, is there something for I2S?

If you're gonna run your TDA1541 non oversampled, and you only got 384*Fs or 768*Fs available,

But I can't make it non-os w/o the 11.2896MHz...

[rfbrw]

Oversampling CXD2500's. Must be a special grade of CXD2500. The ones round here wouldn't dream of doing anything as unreasonable as that. Perhaps it speaks French.