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-   -   Marantz CD273-SE Mods (http://www.diyaudio.com/forums/digital-source/108688-marantz-cd273-se-mods.html)

Thomo 18th September 2007 12:27 PM

Marantz CD273-SE Mods
 
I am currently modding an old Marantz CD273SE which I got for next to nothing.

I am just curious about the TDA1541 dac after having heard so much about it.

Does anyone have the SAA7220 datasheet please? I've scoured the net and had no joy, all the links are not valid any more.

Cheers,

Lee.

Mags 18th September 2007 12:45 PM

Hi Lee.

You can find it here http://www.datasheetarchive.com/preview/2996327.html

Cheers,
Mags.

Thomo 18th September 2007 01:30 PM

Thanks very much;)

Aside from replacing the caps, are there any other tweaks to be made to the SAA7220?

Lee.

philpoole 18th September 2007 03:51 PM

If you get the chance to fit a clock module in the player, then consider reclocking the I2S leaving the SAA7220 before it enters the TDA1541A. This should hopefully remove jitter that might be created by the SAA7220.

Any opportunity you can get to isolate the power rail for the SAA7220 from the rest of the player should also be taken if possible.

Another option is to bypass it and go NOS.

Thomo 18th September 2007 05:46 PM

Hi, thanks for your reply. I do have a spare clock here, but it is set at 16.9mhZ for a CD63. Is it possible to change the clock frequency of the cd273? It is a lower frequency than the cd63.

I think I'll leave nos alone for now, I think that I would have to re-do the analogue filter to filter the rubbish out wouldn't I?

New regs and an extra tx will definitely be going in.

Lee.

Thomo 19th September 2007 09:29 PM

Quote:

Originally posted by philpoole
If you get the chance to fit a clock module in the player, then consider reclocking the I2S leaving the SAA7220 before it enters the TDA1541A. This should hopefully remove jitter that might be created by the SAA7220.

Any opportunity you can get to isolate the power rail for the SAA7220 from the rest of the player should also be taken if possible.

.


Hi again. Is there any chance of some more info on how to do this please? I have been reading quite a bit about the dac chip, but I'm still a relative noob to digital circuits but learning fast!

Would reclocking the i2s mean leaving the standard xtal where it is (next to the SAA7220)? Then cutting a trace, and feeding an external clock into the TDA1541 at pin 2 or pin 4? If this is correct do they not have to be syncronised?

I have extensively modded many cd63's but in those you just re-clock the dac and the servo, which is easy.

Lee.

Thomo 20th September 2007 09:14 AM

Pics
 
Pic of the shoebox on my (unfinished) diy rack:

http://img341.imageshack.us/img341/3...ack1yn1.th.jpg

And as original:

http://img411.imageshack.us/img411/9...oardzr7.th.jpg


Lee.

SimontY 20th September 2007 01:54 PM

Nice Lee, how does this thing sound?

Simon

philpoole 20th September 2007 03:58 PM

Hi Thomo,

I had a TDA1541A running in NOS mode completely unfiltered - and it worked fine. HOWEVER, there is a chance that all that ultrasonic hash can damage tweeters if your amp does successfully amplifier it. So be careful if you do the same.
Besides, since having gone 4x oversampling (with an SAA7220) I can safely say, if you do it properly, you'll be happier with oversampling. There's tons more detail.

To reclock the I2S on this I mean; yes disable the crystal, feed in the clock into where the crystal did on the 7220 (so the clock feeds the 7220, and the 7220 feeds the decoder chip and everything else), and then the interesting bit (and its not really tricky).....
Get hold of quad d type flip flop chip (I use a 74HC174 {I think - I might have to double check that}) feed the I2S outputs from the SAA7220 into three data (D) inputs, and feed the Q outputs to the relevant I2S inputs on the TDA1541A. Feed the clock into the clock (CLK) input of the '174 chip.

And, you need keep the frequency the same (you can't go up to 16Mhz with a CD63 crystal I'm afraid). If you build a Kwak clock or similar, you can use the redundant one in your player.

Hope that helps.
Cheers,
Phil

philpoole 20th September 2007 04:08 PM

[quote]Would reclocking the i2s mean leaving the standard xtal where it is (next to the SAA7220)? Then cutting a trace, and feeding an external clock into the TDA1541 at pin 2 or pin 4? If this is correct do they not have to be syncronised?

I have extensively modded many cd63's but in those you just re-clock the dac and the servo, which is easy.
[\quote]

Sorry. Just to confirm. My description above does not feed the external clock into the '1541.
It is used, as well as clocking the system, used to synchronise the I2S - not to make sure it is sync'ed as such, but as an attempt to reduce jitter.

If you've done reclocking on a CD63, this should be just as easy for you.


However, I've just noticed this is a TDA1541 - not a TDA1541A - so you might have to feed the external clock into (I think, but I've never used a non-A version) pin 4 (please double check that one!).

Another mod you could do is upgrade the TDA1541 to a TDA1541A. You'll have to lift a couple of the pins and apply a 470pF capacitor across them, and the I2S input pins might be slightly different (pff the top of my head, disconnect pin 4 and connect it to pin 2.

Cheers,
Phil


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