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.
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.
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.
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.
philpoole said:
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.
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
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
SimontY said:
It sounds surprisingly good. In standard form, with all the old Cerafines you can see in the picture it was still better than a standard CD63KI IMO.
I've replaced the diodes with Schottky's and many of the elco's with Nichicon PL, Rubycon ZL and a couple of BG's. The results were way better than my cd67 with the same level of mods. It's not really that far behind my highly modified cd67!
I will re-clock the thing once I can figure out what size cap I would need to convert my Superclock to 11mhz. In the mean time I will add an extra tx and a couple of regs.
Lee.
Nice one Phil, thanks for that it's all much, much clearer now.
I have read a few of the threads on the 1541 and was very interested but still quite confused, especially about the DEM re-clocking.
I'll definitely give the flip flop/i2s idea a go.
Don't suppose you have any idea what the little upside-down board is do you?
Lee.
I have read a few of the threads on the 1541 and was very interested but still quite confused, especially about the DEM re-clocking.
I'll definitely give the flip flop/i2s idea a go.
Don't suppose you have any idea what the little upside-down board is do you?
Lee.
Hi Lee,
Glad to be of service
I was going to ask you the same thing about the little board!
It looks like its probably going into pin 1-5, if its going into the '7220 at all, which would be a data input pin of some type.
However, that leg in the photo might be for mechanical support, and it might be a regulator for something else.
It doesn't look particularly stock to me.
DEM reclocking is confusing intially, and only applicable to the TDA1541A.
Cheers,
Phil
Glad to be of service
I was going to ask you the same thing about the little board!
It looks like its probably going into pin 1-5, if its going into the '7220 at all, which would be a data input pin of some type.
However, that leg in the photo might be for mechanical support, and it might be a regulator for something else.
It doesn't look particularly stock to me.
DEM reclocking is confusing intially, and only applicable to the TDA1541A.
Cheers,
Phil
Hi Allan.
I think it's very similar to the Philips CD160 also. Thanks for letting me know, it may be easier to find some mods for the CD65.
Have you done any mods to yours? I am curious about the potential of these players after having heard so much good about the TDA1541.
Don't suppose you know what the little board is do you?
Cheers, Lee.
I think it's very similar to the Philips CD160 also. Thanks for letting me know, it may be easier to find some mods for the CD65.
Have you done any mods to yours? I am curious about the potential of these players after having heard so much good about the TDA1541.
Don't suppose you know what the little board is do you?
Cheers, Lee.
(hurray! I got the quote thingy right!)
Well Lee,
I had a relatively heavilly modded CD63 once (no where near to the levels of Simon's or Rowe's mods) and, when it unfortunately died, I headed off down the TDA1541A route.
I was gobsmacked how such a simple circuit compared to the CD63 (admittedly NOS, but with relatively lower on board frequencies, very simple regulation, no reclocking {to start with} etc) sounded so good. At least comparable to the modded CD63.
This was a standalone DAC, so it was easier to work on than a CDP (it has catastrophically failed less than my CD63 did
), but I then added a clock module, redid the regulation for the DAC chip (lm317/337 followed by TL431), got the SAA7220 running (that was a whole new world of pain and comedy for me - there's a thread somewhere on that one - but please don't laugh too much 
) - so 4x oversampling, and I can safely say its the nicest source I've ever owned. Perhaps not up there with Simon's or Rowe's, but it sounds great.This DAC is fed balanced i2s, so there is no conversion to SPDIF, and each subsection (balanced (RS423) i2s receiver, clock module, SAA7220, i2s reclocker, TDA1541A, opamp I/V (next project to go discrete) ) is seperately regulated. The analogue and DAC sections are regulated with LM317/TL431, and the digital circuits are regulated with LM317/7805.
I learnt from modding my CD63 that seperate regulation and reducing power rail interference really did make a big difference. Its typically trickier in an actual player, but still worth doing if you can.
Some say the 1541 isn't as good as some other DACs, but a similar number defend it. And it is common knowledge that the SAA7220 isn't the best digital filter in the world.
However, they aren't rubbish - not by a long shot.
I've still no idea what that board is though - unless its a format converter (is the decoder non Philips or something?).
Cheers,
Phil
philpoole said:
I dunno Phil, why don't you pop up to Sheffield and listen?
Having been listening to a Rotel RCD-865 briefly, my opinions about my CD63 are reinforced - that it sounds incredibly detailed, dynamic, rich and solid, with very clear precise treble. But it does still sound a little forward and can, at times, be slightly brash. I'd love to hear what else is out there...
Simon
That's interesting.
One thing I expected when going to 4x oversampling was a return to a very bright source, quite harsh and a bit forward.
The original player that I pulled the '7220 out of sounded like that for sure (a Philips CD610 - but it was using a TDA1543, not sure how much difference that makes).
Anyway, when I had it working first of all (without the clock module, and without i2s reclocking) it might of sounded like that, but now it simply doesn't.
Perhaps, there is slightly less bass (as the treble response is increased when oversampling this isn't really a surprise), and the treble detail is much better than in NOS, but it doesn't sound harsh or particularly bright for CD.
If I'm ever in yorkshire for long enough, I'll try and get over and we can do a comparison maybe?
If I can get to the next meet, I shall bring my source with me.
Cheers,
Phil
P.S. what's inside the RCD-865?
One thing I expected when going to 4x oversampling was a return to a very bright source, quite harsh and a bit forward.
The original player that I pulled the '7220 out of sounded like that for sure (a Philips CD610 - but it was using a TDA1543, not sure how much difference that makes).
Anyway, when I had it working first of all (without the clock module, and without i2s reclocking) it might of sounded like that, but now it simply doesn't.
Perhaps, there is slightly less bass (as the treble response is increased when oversampling this isn't really a surprise), and the treble detail is much better than in NOS, but it doesn't sound harsh or particularly bright for CD.
If I'm ever in yorkshire for long enough, I'll try and get over and we can do a comparison maybe?
If I can get to the next meet, I shall bring my source with me.
Cheers,
Phil
P.S. what's inside the RCD-865?
philpoole said:
Excellent.
The Rotel is full of Black Gates and polystyrene filter caps! Amazing quality got £20 on Ebay.
http://www.diyaudio.com/forums/showthread.php?postid=1305302#post1305302
Simon
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.