Building the ultimate NOS DAC using TDA1541A

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#567
My dear rfbrw,
The whole thread is about divulging a certain approach to filterless balanced DAC and possibly helping the thread starter to better it.
Not me, I'm just a humble dilettante that admires people who can deal with those issues like develloping a DAC from scratch and who loves to encourage them... that's all (well, I can plan a DAC but can't devellop it :angel: )

Besides, ecdesigns is stuck to his main idea and thinks his DIDAC sounds excellent. I don't believe anybody would convince him to change his approach...

Enough...

Best regards,
M

PS: if you show me your DAC I will admire you too :hbeat:
 
#569
maxlorenz said:
My dear rfbrw,
The whole thread is about divulging a certain approach to filterless balanced DAC and possibly helping the thread starter to better it.
Click to expand...

Short of making it smaller or using a better dac, there isn't really much left to improve upon. As you say the OP is convinced of the superiority of his approach and so that pretty much closes off all other avenues.
If you'll excuse me, I have a '5843 to put back. I think thats enough self-flagellation for tonight.
 
#571
rfbrw said:



Why bother, my PCM63 is always going to be bigger than your puny little TDA1543 no matter how many you stack up.
Click to expand...


Hi rfbrw !

I see that BurrBrown brought out another dac after the PCM63 , namely, the PCM1702...
Is this IC any better than the '63 ? Linn used this as a relacement to the '63 in their Numerik ...'

Quote from 'net ..."Replacing the DAC is simply a matter of inserting a pair of small pcbs with the new DACs mounted on them into the sockets that once held the PCM63s"

http://stereophile.com/digitalsourcereviews/930/index8.html

what do you think?
cheers,

-Andy-
 
#574
Ehm,

Andy, my quote [could bring up even more] is coming from the conclusion part of the article, why You insist on quoting the introduction .
According to my [some decades] magazine reading experience this article is a good example of saying "caution! BS" for the proposal of changing the Dacs. As far as an audio reviewer could go..

A technical sidenote: these two dacs are NOT totally interchangeable.
There is a shift of emphasis from Wordclock conversion to BCLK conversion. So for me that proposal of Linn sounds even more strange.

And, rigthfully, from that article it emerges that while changing dacs brought up problems, the accordingly re-configured updated implementation IS a success.

Ciao, George
 
#575
George -

Your insight is much appreciated 😀

My goal though, is to find out (by some general consensus, or at least from someone who has more experience with dac's than myself) whether or not these newer dac ic's are indeed better sounding than the older types...
Or, put in another way - do I stick with my Copland cda288, mod it to the hilt...or, take another route with another unit/design ?

Can anyone point out any flaws in the Coplands design that can be improved ? {JohnW - any comment ?}

thanks,

-Andy-
 
#576
Joseph K said:
There is a shift of emphasis from Wordclock conversion to BCLK conversion.
Click to expand...

I've seen a number of references to this, the most notable being in the datasheet but I've always felt it was open to interpretation.
The most common interpretation seems to be that LE goes low, the dac counts 4 BCK cycles and out pops the current. This makes perfect sense and is certainly in accordance with the diagrams shown in the datasheet. Thing is with a number of digital filters, BCK isn't running at the transition of LE. With the PMD100, it hasn't been running for anything up to the last 14 cycles and won't start again for another 2 after LE goes low. From past NOS experiments I know the dac will work even if BCK doesn't start up until 8 cycles past LE going low.
With the above in mind I tend to the view that LE still triggers conversion but the current does not appear until after a period of time equal to 4 BCK cycles.
 
#577
NjoyTHEMUSIC said:

My goal though, is to find out (by some general consensus, or at least from someone who has more experience with dac's than myself) whether or not these newer dac ic's are indeed better sounding than the older types...
Click to expand...

This way lies madness:crackup:.
In this thread the TDA1541A is clearly King of the hill. In the dddac threads it is the TDA1543. With some it is the TDA1545A. In the 300+ page long Marantz thread, some are getting excellent results with delta sigma dac SM5872. I've always felt the PCM63 to be the dogs but the Isodac mob will tell you it is the PMD100/SAA7350 combo. The Naimites have the TDA1305. I'd say that doesn't count for much but then again the same dac does a pretty decent job in the Dacmagic. For the APL lot it is AKM or nothing. There are also those oddities who like the TDA1547 but they are only visiting earth so I wouldn't bother too much with what they say, assuming you can understand them. Waiting in the wings is the PCM1704 which seems to capable of excellent results with or without a filter. And then there is the PCM1738 and the 1792 and the AD1853 and the CS4398 and the..... Then there the business of digital filters both off-shelf and proprietary.
Don't even think about looking for a definitive answer, there isn't one.
 
#579
Maybe there is an answer to Andy, though: as there is a probable technical difference between the two dac chips, it is definitely not a straithforward step ahead to put the new chips into a design made for the old ones. I'm quite sure the Copland uses LE reclocking, and as it can be seen it either will or will not work properly with the pcm1702.

Maybe he should open an another thread for upgrading his player, apart from the dacs? In a new thread it could be even clarified, what exactly is the problem with the old player? Hope it's better founded than a general tweaker's bug bite? With such a beautiful and not exactly cheap old design.

Ciao, George
 
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