Marantz cd-52 clocking question

[moemoe]

Hi All,

I recently purchased a used Marantz CD52 unit with the intention to mod it and implement my own non-os DAC module with direct i2s input from the SAA7310GP.

Interesting enough, while tracing the wirings of the SAA7310GP I found that the xtal_in (pin 26) is not connected to any crystal oscillator! The PCB layout is rather intricate and without any service manual on hand, you can imagine it's a tough job trying to put all the pieces together. In any case, I did find a crystall oscillator but it is only connected to the stock DAC chip (SAA7350GP); there's no trace from the DAC XSYS1 pin back to the SAA7310GP.

In case you are wondering about the layout, the DAC chip is connected to a NPC SM5840FP digital filter for up-sampling purpose and it in turn is connected to the micro-controller and the SAA7310GP.

Qn1: The music reporduction of this unit is fine. That seems to imply that it is not necessary for the SAA7310 chip to have have clock input or sync. But...how can this be the case? I mean, surely the SAA7310 chip must need to know when to clock the data out to the Digital Filter/DAC, right?

Qn2: for my mod, I intent to re-use the crystall oscillator and implement the Kwak Clock with clock input to the SAA7310. However, I'm not sure whether this may screw things up. I doubt so but would like some confirmation from the guys who have done mod on Marantz CD52 or with in-depth knowledge of the SAA7310.

Thank you in advance for your help on the above!

[Bricolo]

Hi,


Does your CD-52 have 2 PCBs? One for the PS/Controller/Decoder and another for the Filter/DAC/Output Stage?
If yes, it certainly looks like my CD-62. I don't have the service manual for it (if anyone has, please tell me!) but I made some schematics myself by looking at the traces.

If you don't find the datasheets for the ICs in your player, tell me, I'll send you them


Alex

[moemoe]

Hi Bricolo,

No, the CD52 has only one PCB for all the components. Thanks for your offer on the datasheets. I have the datasheets for the SAA7530 and SAA7310 but not the SM5840FP. If you have it, will appreciate if you email it to me.

Thanks,
Moe

[Elso Kwak]

Originally posted by moemoe
Hi All,

I recently purchased a used Marantz CD52 unit with the intention to mod it and implement my own non-os DAC module with direct i2s input from the SAA7310GP.

Interesting enough, while tracing the wirings of the SAA7310GP I found that the xtal_in (pin 26) is not connected to any crystal oscillator! The PCB layout is rather intricate and without any service manual on hand, you can imagine it's a tough job trying to put all the pieces together. In any case, I did find a crystall oscillator but it is only connected to the stock DAC chip (SAA7350GP); there's no trace from the DAC XSYS1 pin back to the SAA7310GP.

In case you are wondering about the layout, the DAC chip is connected to a NPC SM5840FP digital filter for up-sampling purpose and it in turn is connected to the micro-controller and the SAA7310GP.

Qn1: The music reporduction of this unit is fine. That seems to imply that it is not necessary for the SAA7310 chip to have have clock input or sync. But...how can this be the case? I mean, surely the SAA7310 chip must need to know when to clock the data out to the Digital Filter/DAC, right?

Qn2: for my mod, I intent to re-use the crystall oscillator and implement the Kwak Clock with clock input to the SAA7310. However, I'm not sure whether this may screw things up. I doubt so but would like some confirmation from the guys who have done mod on Marantz CD52 or with in-depth knowledge of the SAA7310.

Thank you in advance for your help on the above!

Hi moemoe,
The original crystal was probably connected to the SAA7350.
So you have to connect the KWAK-CLOCK here too!
From there the clock is further linked to the digital filter and digital signal processor.
Just remove the crystal, the two small caps connected to it and the 100k or 1M resistor.
See fig. 12 of the datasheet:
http://www.ultranalog.com/data/frits/saa7350_bw.pdf
BTW instructions for the CD52 are also on www.lcaudio.dk

[moemoe]

Hi Elso,

"The original crystal was probably connected to the SAA7350.
So you have to connect the KWAK-CLOCK here too!"

Yes, the crystal is directly connected to the SAA7350. I was able to trace the wirings with the help of the SAA7350 datasheet. However, since I'm going to use my own TDA1541-based non-os DAC, I was thinking of connecting the Kwak Clock straight to the SAA7310. One good reason of doing that, I think, is because I would like to input the clock signal directly to the SAA7310 instead of subjecting it to potential noise as it winds its way along the PCB from the SAA7350 to wherever it's supposed to go.


"From there the clock is further linked to the digital filter and digital signal processor."

No such luck...I look at the layout a few times and there's just no clock input back to the digital filter and the SAA7310. The XTAL_in pin of the SAA7310 is left opened and not linked. The XSYS1 pin of SAA7350 is also left opened and not linked. Frankly, I myself is quite puzzled by this. The only explanation I can think of is that there's a internal VXO inside the SAA7350 that's doing the clocking and synchronisation (at least the datasheet seems to imply this)

[guido]

It is possible to remove the DAC and digital filter and connect the clock direct to the SAA7310. Did once myself when i removed a 7220 dig filter from a player (clock was connected to the 7220, as usual).

However, the xtal needs to be the 11.xx MHz xtal found in those old philips based players.

I cannot imagine that there is nothing connected to pen 26 (unless the 7310 is a DIP version and it is pen 19).

Regards,GuidoB

[Bricolo]

take a multimeter and test if the the 7310's pin 26 (Xtal1 or clock input) is connected to the digital filter's clock output (not to the cristal! look at the filter's datasheet, it certainly has a buffered clock output)


In my CD-62, the 7310's pin 26 seems to be unconnected, but in fact it is, and the PCB trace is under the chip, so not visible

[Elso Kwak]

Originally posted by moemoe
Hi Elso,

"The original crystal was probably connected to the SAA7350.
So you have to connect the KWAK-CLOCK here too!"

Yes, the crystal is directly connected to the SAA7350. I was able to trace the wirings with the help of the SAA7350 datasheet. However, since I'm going to use my own TDA1541-based non-os DAC, I was thinking of connecting the Kwak Clock straight to the SAA7310. One good reason of doing that, I think, is because I would like to input the clock signal directly to the SAA7310 instead of subjecting it to potential noise as it winds its way along the PCB from the SAA7350 to wherever it's supposed to go.


"From there the clock is further linked to the digital filter and digital signal processor."

No such luck...I look at the layout a few times and there's just no clock input back to the digital filter and the SAA7310. The XTAL_in pin of the SAA7310 is left opened and not linked. The XSYS1 pin of SAA7350 is also left opened and not linked. Frankly, I myself is quite puzzled by this. The only explanation I can think of is that there's a internal VXO inside the SAA7350 that's doing the clocking and synchronisation (at least the datasheet seems to imply this)

Hi Moemoe,
No problem connecting the clock directly to the SAA7310. See the SAA7310 datasheet, if you are using your own DAC TDA1541 NON-OS.

[Bricolo]

Elso, what will happen if he doesn't mod his player for NOS-OS, and connects the new clock to the decoser rather than to the DAC ?

The filter and DAC won't have any 11Mhz clock anymore.

The TDA1541A don't need one, but the 7322 and 7350 do

[jean-paul]

moemoe, datasheet of SM5840 can be found here:

http://www.npcamerica.com/discontinued_part_list.htm

Just remove the crystal, the two small caps connected to it and the 100k or 1M resistor.

That must be a mistake Elso. I would leave the 100k or 1M in place The 1k must be omitted. Had some nasty side-effects when the resistor from Xin to Xout wasn't there.