Absolute top tier DAC for standard res Redbook CD

@gdhal
Hi Hal,

No, my statement was not intended to imply that musical information is lost when data having more bits per sample and a lower sample rate is converted to fewer bits per sample at a higher sample rate. From a theoretical standpoint nothing will be lost if the increase in sample rate is sufficient to compensate for the decrease in bits per sample.

And while I do not have detailed familiarity with the specifics of modern delta-sigma DAC designs, user reports of good results with high end delta-sigma designs, published measurements, comments by some who have such familiarity (such as the comments provided by Steve and Shadorne yesterday), as well as my general belief (shared by many others here) that in audio how well a chosen design approach is implemented is usually more important than which approach is chosen, all lead me to believe that "throwing away the original samples" (as referred to by Schiit) is a non-issue in modern high end designs.

Best regards,
-- Al

Gentlemen, I want to thank you for the fascinating discussion and compliment you all on the level of decorum, respect and intelligence all have maintained!!! We have had multiple designers and manufacturers involved along with many enthusiasts and this “side debate” has stayed mature and informational for all to read. It just proves the quality and intelligence of those involved in helping keep this wonderful thread weaving and flowing for all these years. 

Sorry for the intrusion. But it makes a Pappa proud. :)

Charles I agree with you, but let’s put it this way. Say the Bricasti best the MSB, well there has not been any highly rated RTR yet that I have heard to be king. There can only be so many  one can test , but this may possibly show I prefer delta sigma. The point is I listen to and enjoy what sounds good. I’m not trying to bash RTR but so far to me it does not have a good track record.

It’s funny how the reviewer thought the total dac had more detail. I totally found the opposite. Not only more detail but also much more open and much bigger soundstage beyond the speakers for the Bricasti. When I told the total dac owner about not very open, he said, oh you have to try my new 20,000.00 dac seven. Oh my did I laugh to myself. 

The best explanation is the “measuring cup analogy” in Stereophile 1990. Nothing is “thrown away” - Delta-Sigma is just a different (more accurate measuring cup) method for conversion to analog. R2R methodology lost the technical battle about 20 years ago - R2R is too expensive and too inaccurate to be a leader in DAC technology. R2R relies on impossible accuracy in analog devices whilst Delta-Sigma elegantly uses mathematics to achieve superior performance in a simple robust way.

The latest hybrid ESS approach - massively parallel one-bit DACs all on the same DAC chip with random selection to reduce noise is some 30dB+ better in THD+N - massively outperforming R2R for a fraction of the cost. Technical progress is wonderful!

As far as I can see, the marketing of R2R is highly misleading - full of all kinds of false insinuations - “throwing away data” - simply not true, not bit-perfect (when delta-sigma is far more accurate), “facsimile” - ironically R2R is actually the poor quality analog facsimile, “guessing” - again ironic because R2R actually has built-in massive non-linearities that makes the accuracy no better than a guess where delta-sigma is many times more accurate.

Here is a basic description of the different approaches:

”The same reasoning underlies the development of bit-stream decoders. The problem with a conventional digital/analog converter (DAC) is that its operation involves mainly analog processes and is therefore approximate. A 16-bit DAC contains a precision current source and an array of 16 switches. Each switch is connected to a resistor, and the resistors are supposed to be scaled in exact 2:1 ratios so that each switch, when opened, will contribute exactly twice as much current to the output as the switch below it. The switches are controlled by the 16-bit codes from the CD; thus by opening and closing in various combinations, a total of 65,536 different output values can be generated.

But the topmost switch (the most-significant bit, or MSB) contributes 32,768 times as much current as the least-significant bit (LSB). If the MSB current is in error by as little as one part in 32,768, the effect of the LSB is swamped. In most CD players it is; few 16-bit DACs operate to better than 15-bit accuracy. The practical result is that most CD players are non-linear at very low signal levels, reproducing small signals at the wrong levels and with added distortion. Keep in mind that this problem arises not from the digital code itself but from small errors in an analog quantity—the current produced by the DAC for the several most-significant bits.

For comparison, imagine that you were assigned to fill a bucket with a known amount of water, using measuring cups varying in size from one ounce to 64 ounces. Even if you use care in filling the largest cup, it might contain 63.7 or 64.5 ounces instead of 64; you can’t be sure that it contains exactly 64 times as much water as the smallest cup. But there is a way to obtain an exact result: use only the one-ounce cup, and transfer its contents to the bucket 64 times. The capacity of the cup may not be exactly one ounce, but as long as you fill it the same way each time, the total amount transferred will be proportional to the number of refills—an exactly linear relationship. This is the idea behind 1-bit decoding. In place of a method whose result depended on slightly uncertain analog quantities (the currents in the DAC), we have adopted a simple counting scheme—a purely digital process.

Of course with a small cup you’ll have to work fast, but in modern digital electronics that’s not an obstacle.”


Read more at https://www.stereophile.com/content/pdm-pwm-delta-sigma-1-bit-dacs-peter-w-mitchell#44ZdP17jRzTtUGor...