PCM to DSD...the new PS Audio DAC

[rbbert]

... Dudley used to be a great..

Fixed that. Based on much of his last year's published writing I'm afraid he might have suffered a significant loss in his cognitive facilities

 

[Andre Marc]

Fixed that. Based on much of his last year's published writing I'm afraid he might have suffered a significant loss in his cognitive facilities

Yikes!! any specific examples?

 

[tailspn]

tailspn please do not ruin my day; I love the forum conclusion reached that nearly all SACD/DSD is transcoded to PCM and also nearly all PCM DACs convert to SDM

I won't ruin you day Orb, honest.

I believe the debate on this thread is about semantics. Thinking that multi-bit PDM (that which goes on inside most DAC chips when fed a DSD (1-bit two level bit stream) is PCM. j.phelan is correct in that many DAC chips transcode the 1-bit two level bit stream decoded off an SACD into multi-bit. But they do that at the 2.82MHz bit rate, or a multiple of that. They do not decimate it down to a digital value based 2's complement binary PCM word(s).

Confusing multi-bit PDM (Pulse density Modulation) that has no absolute digital word amplitude level value(s) with PCM that is only absolute digital word amplitude values, is what I believe the fundamental misconception..

 

[Andre Marc]

According to the manufacturers, at least Cary, Playback Designs and Oppo will all decode DSD directly to analog without PCM conversion. I'm sure there are others, those are just some that have come up in recent discussions.

This was put together by a solid group of DSD guys including Sonore.
https://docs.google.com/spreadsheet/lv?key=0AgVhKcl_3lHfdFVyenBBNjNpQ2lieG81WGpqQTNfVUE#gid=0

 

[Andre Marc]

I won't ruin you day Orb, honest.

I believe the debate on this thread is about semantics. Thinking that multi-bit PDM is PCM. j.phelan is correct in that many DAC chips transcode the 1-bit two level bit stream decoded off an SACD into multi-bit. But they do that at the 2.82MHz bit rate, or a multiple of that. They do not decimate it down to a digital value based 2's complement binary PCM word(s).

Confusing multi-bit PDM (Pulse density Modulation) that has no absolute digital word amplitude level value(s) with PCM that is only absolute digital word amplitude values, is what I believe the fundamental misconception..

I believe many of Michael J's comments here are valuable.
http://www.audiostream.com/content/mytek-stereo-192-dsd-dac-0
http://www.audiostream.com/content/qa-michal-jurewicz-mytek-digital

 

[j.phelan]

Orb said (as a "conclusion" of this thread) that "nearly all PCM DACs transcode to SDM". I didn't say that, for one.

But two, if we listen to the tech-guru of AMR, there are no true 1-bit DACs.

And - it should be noted that many high-end brands don't even (try) to do 1-bit - Zanden, MSB and Totaldac are a few.

 

[Andre Marc]

Orb said (as a "conclusion" of this thread) that "nearly all PCM DACs transcode to SDM". I didn't say that, for one.

But two, if we listen to the tech guru of AMR, there are no true 1-bit DACs.

Many high-end DACs don't do this anyway - even as advertised. Zanden, MSB and Totaldac are a few.

Thorsten is extremely biased, having publicly declared his dislike for DSD. He has also publicly said that 44.1/16 bit has all the resolution needed. Period.
Thorsten is brilliant, but has some distinctly odd views on many things. He designed the iFi iDSD Nano and Micro despite his dislike of DSD. I have those
coming in, and i have heard from multiple sources they sound really, really good.

 

[Andre Marc]

Orb said (as a "conclusion" of this thread) that "nearly all PCM DACs transcode to SDM". I didn't say that, for one.

But two, if we listen to the tech-guru of AMR, there are no true 1-bit DACs.

And - it should be noted that many high-end brands don't even (try) to do 1-bit - Zanden, MSB and Totaldac are a few.

A good read, while we are at it.
Q&A with Thorsten Loesch of AMR/iFi
http://www.audiostream.com/content/qa-thorsten-loesch-amrifi

 

[Orb]

Orb said (as a "conclusion" of this thread) that "nearly all PCM DACs transcode to SDM". I didn't say that, for one.

But two, if we listen to the tech-guru of AMR, there are no true 1-bit DACs.

And - it should be noted that many high-end brands don't even (try) to do 1-bit - Zanden, MSB and Totaldac are a few.

Definitely not directed at you J-Phelan and I could had made it clearer, sometimes forget readers may not be aware of previous discussions.

It relates to many discussions possibly before you joined and if look back should infer forum rather than specifically you; in those threads the primary POV (I do not necessarily agree with the POV as like SACD/DSD there are native examples) was that there are no or very few real PCM DACs due to SDM being used.
Hence why I state "I love the forum conclusion" rather than say "thread conlusion" or specific names.
Just comes down to history and following a lot of threads on this subject, that have gone on for maaaaaaaany pages in the past so added a bit of light heartedness
Thanks
Orb

 

[j.phelan]

No problem Orb -

We were all duped by Sony/SACD in 1999. I for one, thought it was a true advance.

But it never did make sense - coming out so soon after 20-bit/high-sampled music (for the audiophile, released as CD) and about a dozen years after the mass-market bought CD players.

Truncating a 20-bit recording was not harmful, like many of us thought. It gave recordists "room" in the studio, for signal processing (which they needed). One reason why Red Book works - it was recorded higher.

For the record - I never supported the low-bit format but did support ladder-DACs on playback. These made more sense, from a noise perspective. The cheaper way was SDM - but cheaper was never better in high-end audio. Why EMM had to re-build them for their latest units.

The only thing with ladders was their need for more power supplies...

But - it doesn't matter anymore - the future is the Ted Smith idea - or NAD M2. Both concepts do *away* with the DAC....

 

[Bruce B]

Who was the first to do away with chips? EMM Labs/Andreas Koch?

 

[asiufy]

dCS, no?

 

[Orb]

Rob Watts did his first FPGA DAC I think 1997 (before Chord Electronics and DAC64 that enabled him to take the design further and more commercially)
Probably one of the earliest examples of bespoke DAC using FPGA, whether first to do away with traditional OEM DAC Chip *shrug*.

Cheers
Orb

 

[jkeny]

Rob Watts did his first FPGA DAC I think 1997 (before Chord Electronics and DAC64 that enabled him to take the design further and more commercially)
Probably one of the earliest examples of bespoke DAC using FPGA, whether first to do away with traditional OEM DAC Chip *shrug*.

Cheers
Orb

Was this when he was one half of Deltec Precision Audio' (DPA) in the 90s?

 

[Orb]

Was this when he was one half of Deltec Precision Audio' (DPA) in the 90s?

Yeah
They were developing an innovative DAC but from what I remember costs were high, to achieve similar results but with a reduced manufacturing cost Rob (or both) switched to developing solution on FPGA chipset.
Cheers
Orb