2xDSD - Smoke and mirrors, or will there appear better masterings on it?

[asiufy]

None that I'm aware of - probably for the reason that the TDA1541A isn't being manufactured so any prospective maker using it would have to secure reasonable stocks prior to going ahead with a product. Seems unlikely given the sticky supply situation. Those currently in manufacture with this chip got stocked-up years ago AFAIA.

Ah, that chip is not being made anymore? I see... And again, nothing better replaced it, from the same manufacturer or some other brand?


alexandre

 

[opus111]

No, that part dates back to the mid 1980s before the advent of S-D, which then became the dominant architecture for DACs owing to its considerable price advantage and ability to scale along with Moore's Law.

There are I believe DACs which might be able to match its performance but aren't targetted at the audio market so need a fair amount of engineering to make them suitable. I have some sample devices which I intend to deploy to develop a design to rival or even perhaps exceed the TDA1541A but that'll be at least a year away.

 

[Nightlord]

What's your quarrel with, say the Sabre32 Reference DAC ?

 

[opus111]

Assuming you mean 'quarrel' metaphorically, then I don't rate it for a few reasons.

Firstly I can't understand how the sample rate conversion is supposed to work, they seem to me to be pulling the wool in the explanations they offer. Added to this there are various independent listening reports from DIYers who say it sounds better operated synchronously. If anyone really does understand how it works I'm game to make an attempt to grok it.

Second its measurements show it suffers from significant noise modulation - I pointed this out in the thread about the Weiss Medea which uses it.

Thirdly it operates at such a high switching frequency its practically impossible to make an output stage linear enough for it and to control its power supplies sufficiently well for the highest sonic results.

As S-D implementations go though, its definitely the best of an otherwise lack-lustre bunch of designs.

Oh I just remembered, there's a fourth issue. It seems from a cursory read of the datasheet it only supports symmetric FIRs in its oversampling chain - that is linear phase ones, I have a preference for minimum phase filters.

 

[Nightlord]

The noise modulation you mention, is that something that doesn't get measured as part of the "DNR of up to 135dB and THD+N of -120dB" specs?

 

[opus111]

Yes that is correct - the DNR is somewhat variable according to the signal level but this effect isn't highlighted in the datasheet. It does however show up on 3rd party measurements of THD+N vs input signal level.

 

[Nightlord]

Ok. What about Wolfson WM8740 - which you'll find in for instance the Cambridge Audio DacMagic Plus ?

Ken Rockwell review/measurements to be found here

 

[opus111]

OK - I went to the THD+N vs level graph to see if there were any noticeable kinks - and at first blush there aren't any showing. Which seems a bit too good to be true.

So to corroborate this I then looked at the THD+N vs frequency plots, 1kHz frequency point, at the various levels. They do not correspond, the THD+N vs level graph shows up to 6dB higher readings than these at the -20, -40 and -60dBfs levels. This indicates to me there's something amiss with the measurement technique used in the former measurement. Perhaps whoever set up the test sequence didn't allow enough settling time after each level change. Hence I conclude that the THD+N vs level plot isn't trustworthy enough to be sure there's no noise modulation occurring.

<edit> I've made an oversight, not being familiar with this piece of test kit. I'd assumed that the graph was THD+N vs level but it might indeed be as marked, THD vs level (excluding noise). Which would mean any noise modulation wouldn't show up on it.

Looking further down, noise modulation is evident on the 11k+12k IMD test - see how the grass has grown up when compared to the single tone tests above - this looks to me to be 10-15dB of noise modulation in going from a single tone (crest factor 3dB) to twin tones (crest factor 6dB). Such is fairly typical of S-D systems.

 

[Nightlord]

Thanks.

 

[Mike Lavigne]

I've had both types of DACs; single bit SDM (MPD-5) and multi-bit r2r (totaldac). My preference is multi-bit DAC playing PCM files. Its tough to really compare formats with a single converter though. Someone with access to the live feed and different ADCs would be in the best position to judge.

interesting.

one thing about the Playback Designs MPS-5 is that it is a progammable dac; they don't use 'off-the-shelf' dacs. and from time to time there are advances in the software.

last week updated software was offered at no cost; it went from release 21 to 23. i did the update in about 15 minutes Friday night. it was a particularly significant increase in PCM performance. more vivid, lower noise floor, more separation of things in the soundstage, more dynamic, greater ease to the music. really a nice improvement.

same benefit in dsd but slightly less in degree of improvement.

i assume the MPD-5 had a similar upgrade assuming you still have it. if you did the upgrade what was your take?

my MPS-5 is now 6 years old and still at the front of digital performance. it does the dsd and 2xdsd as well as great PCM performance.

 

[jkeny]

Yea, I was interested in the manufacturer's comments after a Stereophile review of the MPS-5, in which Fremer gave it a thumbs up on listening tests & Atkinson gave a bad report on measurements:

Editor: We would like to thank both Michael Fremer and John Atkinson for the time and work they put into reviewing and testing our Playback Designs MPS-5 SACD/CD player. We were very pleased that an analog lover like Michael would enjoy our digital player.

Most of the measurement results are generally to be expected from the way they were measured. What differentiates the D/A converter inside the MPS-5 from other, more conventional converters is that it uses all custom algorithms and discrete components that were not designed following classic theories and practices. A large percentage of your charts show the behavior of the MPS-5 in the frequency domain, and only two charts show the time domain, although with rigid sinewaves as test inputs. While this would be totally adequate in most cases, it isn't for the MPS-5. For instance, most of the filter algorithms inside the MPS-5 cannot be described or even defined by feeding them periodic test tones such as sinewaves and looking at frequency charts. They were designed for real music signals, and therefore "listen" to the input signal and vary accordingly, to take advantage of how our ear perceives music, which never even resembles periodic test signals. It is common knowledge that such psychoacoustic criteria hardly ever lead to ideal measurements based on steady-state test signals.

Right from the beginning, the design goals for the MPS-5 were to reach new heights in sonic performance with real music signals rather than optimum test-signal measurements. The result is that the algorithms may not perform optimally from a measurement point of view when they have to process test signals, but, as your review also confirms, they do their assigned job quite well when processing real music signals. As we are always researching new ideas, the next-generation algorithms may very well make these kind of measurements even worse—but we can assure you that it will be for the benefit of sonic performance. Isn't that what we are all after?

Again, thank you for the wonderful review!—Jonathan Tinn, Andreas Koch
Playback Designs

Some cynical people would view his comments as ass-saving but his points I bolded above are cogent to what is being discussed here. It would be interesting to see a new set of Stereophile measurements post this recent software update to see what if any correlation those measurements might have with the improvements heard post S/W update

 

[dallasjustice]

interesting.

one thing about the Playback Designs MPS-5 is that it is a progammable dac; they don't use 'off-the-shelf' dacs. and from time to time there are advances in the software.

last week updated software was offered at no cost; it went from release 21 to 23. i did the update in about 15 minutes Friday night. it was a particularly significant increase in PCM performance. more vivid, lower noise floor, more separation of things in the soundstage, more dynamic, greater ease to the music. really a nice improvement.

same benefit in dsd but slightly less in degree of improvement.

i assume the MPD-5 had a similar upgrade assuming you still have it. if you did the upgrade what was your take?

my MPS-5 is now 6 years old and still at the front of digital performance. it does the dsd and 2xdsd as well as great PCM performance.

I don't have it anymore, so I can't comment on Andreas' update. As far as I'm concerned, it's the single bit design that distinguishes it from a multi-bit DAC.

 

[Hugo Thorsin]

Opus3 will soon offer their back catalogue as DSD downloads. Here is a complimentary track in 2.8 & 5.6MHz DSD. Direct from Master Tape!

www.dsdfile.com

Enjoy!

 

[KBK]

I take no issue with your general argument but wonder where you find this information which conflates auditory and vestibular transduction. How does auditory input encode "3d xyz" or where in the CNS is it correlated with auditory input?

well, Kal, you know how that works. My understanding of it is that it come into the mind differently and that we can learn to add an overlay of what we think we hear from the data. You know, learning of a high level function, based on data at the base level.

If I don't propose it, it will never be explored... and then you and I will never get to do the fish dance, like we always seem to do.

 

[astrotoy]

Opus3 will soon offer their back catalogue as DSD downloads. Here is a complimentary track in 2.8 & 5.6MHz DSD. Direct from Master Tape!

www.dsdfile.com

Enjoy!

Thanks, Hugo. I've just sent in for the sample tracks. I have purchased 10 of the R2R from Opus3 which they dubbed directly from their master tapes. I'm very interested in comparing the DSD versions to their master dubs. Larry

 

[NorthStar]

Opus3 will soon offer their back catalogue as DSD downloads. Here is a complimentary track in 2.8 & 5.6MHz DSD. Direct from Master Tape!

www.dsdfile.com

Enjoy!

Dats Cool!

 

[Hugo Thorsin]

Astrotoy & Northstar! Hope you enjoyed the track! Eric Bibb - Meeting at the building will also be featured of the next Reel Sampler. Since all tapes used for Reel2Reel sampler 1 & 2 were present at the studio the DSD sampler 1 & 2 will contain the same tracks. The full samplers will be available for download in a few weeks.

We've, of course, done tests Reel vs DSD (or should i say Real vs DSD) and though there are slight differences no one has with absolute certainty nailed which input is the reel tape and which is DSD. So to say the least we are very pleased with the result and if quality counts DSD will have a bright future! And seeing the improvements in PCM over time, it will be very exciting to see how far DSD can take high fidelity!

 

[NorthStar]

-- Opus 3 is a good (very good) record label (got a bunch of those on CD/HDCDs).

* Eric Bibb, not much I don't have from him. ...A folk troubadour, with a bluesman's soul.

Nice meeting you Hugo.

Bob

 

[astrotoy]

Astrotoy & Northstar! Hope you enjoyed the track! Eric Bibb - Meeting at the building will also be featured of the next Reel Sampler. Since all tapes used for Reel2Reel sampler 1 & 2 were present at the studio the DSD sampler 1 & 2 will contain the same tracks. The full samplers will be available for download in a few weeks.

We've, of course, done tests Reel vs DSD (or should i say Real vs DSD) and though there are slight differences no one has with absolute certainty nailed which input is the reel tape and which is DSD. So to say the least we are very pleased with the result and if quality counts DSD will have a bright future! And seeing the improvements in PCM over time, it will be very exciting to see how far DSD can take high fidelity!

Great, I have R2R Sampler 1 already. I have collected Opus 3 Vinyl starting in the early 80's. Think I have about 40 of their vinyl albums. Great sonics and very interesting artists - mostly Scandinavian. Eric Bibb is an exception.

Larry

 

[Hugo Thorsin]

Will be very interesting to hear your thoughts on the DSD files! And Jan-Eric has worked with some very talented musicians. And the sound quality is always very life like.

http://www.positive-feedback.com/Issue65/dsd.htm Found this list yesterday! Looks like more and more are going to offer DSD capabilities! Very much looking forward to the Oppo upgrade. Both me and Jan-Eric are big Electrocompaniet fans and their multiplayer EMP3 is based upon the Oppo! Interesting times indeed!