CS4397 dac

[leo]

I got one of these cheap dac pcbs to play about with, its based on the CS4397.

I've changed the PPL filter for the CS8416 as I noticed it was the wrong values, it now locks onto the spdif much better and sounds better too.
I have also changed the op-amp to a OPA2111 and bypassed the coupling caps on the dacs differential output
Voltage is being supplied from ALW super regs

Sound so far isn't bad, its quite a way behind both my diy TDA1541A double crown based dac and diy PCM1794 based one but we'll see how it goes with some more work, never been a huge fan of voltage output dacs but its all good fun

I'm going to build a discrete differential to line out output stage so to ditch the op-amp, also have a play about with the decoupling
Replace the phono in socket for the spdif to a 75R BNC and probably add a pulse traffo on the input



Edit added 01/06/09

I recently had a PM from a forum member under the name of Raptor , he's spent some time going through the mods and thought it would be helpful for others to compile list and info so here it is

- R2 becomes (BC Components minimelf) 3k, C22 becomes 22nF, and C23 becomes (COG/NPO) 1 nF ((Read datasheet for reccommendations))
- Remove and link the pads of the 4 DAC output capacitors, (2.2u 50v C27,C28,C30,C31)
- Remove and link the pads of the output capacitors near RGL socket (10u 16v C6,C54)
((Use your own MKP))
- Link the two exposed pairs of pads underneath on the top and top left of the small IC ((This bypasses it completely.))
- C9 (C7/C13 for TOSLINK) should be REMOVED and replaced by a Vishay/ERO MKP1837 0.1uF or equivalent. (Possibly also a small 0.1uF Ceramic dipped in hot glue to remove some microphonics. SHORT LEADS)
- Lift or unbridge pin 2 of the CS4397 and connect to Pin 16 of the CS8416.
- R8,R9,R14,R17 to 30k WELL MATCHED
- C32,C33,C34,C35 to 150pf SMD or Polystyrene
- R28 and R29 should be missing.
- C17,C20,C2 100uf-220uF Oscon
- C16 100uF Oscon
- C3, C18, C11 can be left alone (Just pulling pins high)
- C25 5.6!!-10uf Tantalum or 5mm MKP.
- C12, C8, C13, C10, C14(C41) bypass with MKP 0.1uF
- C19 should be 1 decimal step smaller than the last filter cap on your +5 supply. (1000ish Not OScon.)
- C21 should be 1 decimal step smaller than C19. (100-220ish Not OScon.)

- Tube out - http://theartofsound.net/forum/showp...&postcount=325 or page 33.
- Digital out - Pages 22-27ish have a board layout referenced from earlier page's schematic. 30-35 have modifications to the components around the opamp socket for output. I suggest just pulling off the DAC's 2.5+v outs with a coupling cap or trafo.

"BTW don't always trust what you read regarding low ESR caps, their not always better in every application" -Leo

[jonners]

I've just ordered one of these after reading this: http://www.lampizator.eu/LAMPIZATOR/...ampizator.html
I will report back when I get it going. Meanwhile, I would be interested to know, Leo, what were the specific changes that you made to the PPL filter?

[leo]

C22,R2 and C23 is the PPL filter for the CS8416, I changed them to whats used in the updated datasheet 3k/1N and 22N , I used a minimelf resistor for the 3k and PPS for the caps

I don't see much point in adding a valve output stage to this type of chip, nothing wrong in it though I guess, beauty with diy

[Marco]

Sound so far isn't bad, its quite a way behind both my diy TDA1541A double crown based dac and diy PCM1794 based one but we'll see how it goes with some more work, never been a huge fan of voltage output dacs but its all good fun

Interesting comments, Leo, and congrats on your latest DAC project.

What's your opinion on the TDA1541 compared to Burr Browns and Wolfsons? Ashley is of the view that Burr Browns are better because they measure better, but my ears, and those of others I respect, tell me nothing beats the TDA1541, whether single, double, or triple-crown. They seem to give music a 'weight' and 'presence', and an 'analogue' type of presentation (in a good sense) that the top modern DAC chips lack, which to my ears are often thin and 'bleached' sounding in comparison.

What are your views?

Marco.

[leo]

TDA1541A double crown is still my favourite chip to date, I've tried and heard so many different commercially made units using BB, Wolfson, AD, Cirrus etc, I've also built quite a few diy dacs using these various chips and I always come back to this classic, implemented correctly no other device has that realism in the midrange, decay of piano that this one has IMHO.

Of course theres a lot of units using this classic chip that sounds god awful, as everything else its the implementation which is why I only stick to diy with this chip.
Most components have moved on since these chips was first made and used in commercial equipment, problem regarding dac chips is the latest and so called greatest ones have the important stuff like oversampling, current to voltage etc locked inside the actual chip so your limited to what you can do, where as the older ones have it all external giving you far more to tweak about with

Just my opinion of course

[leo]

The only other dac I have kept hold of is a diy based around the BB PCM1794, its very good but I still prefer the old classic

The CS4397 I'm playing about with now is basically for a bit of fun on the cheap

[Marco]

TDA1541A double crown is still my favourite chip to date, I've tried and heard so many different commercially made units using BB, Wolfson, AD, Cirrus etc, I've also built quite a few diy dacs using these various chips and I always come back to this classic, implemented correctly no other device has that realism in the midrange, decay of piano that this one has IMHO.

I totally agree! I think I'll flag this one up as a sticky for Ashley

Of course theres a lot of units using this classic chip that sounds god awful, as everything else its the implementation which is why I only stick to diy with this chip.

Yes indeed - implementation is all, but correctly implemented, the TDA1541 is the best DAC chip ever made bar none. It's quite simply the definitive choice for discerning audio enthusiasts

Marco.

[leo]

I don't care too much what others say or think about this chip, until somebody comes along with a unit that I think sounds better than what I use I'll stick with this old classic
I give everything a chance even the hyped up stuff, still waiting to have my socks blown off though

[Marco]

Same as me, Leo. You are indeed a man of class

Marco.

[jonners]

Originally Posted by leo

C22,R2 and C23 is the PPL filter for the CS8416, I changed them to whats used in the updated datasheet 3k/1N and 22N , I used a minimelf resistor for the 3k and PPS for the caps

I don't see much point in adding a valve output stage to this type of chip, nothing wrong in it though I guess, beauty with diy

Thanks for your help.
John