Schiit Yggdrasil -- 21 bit?


Schiit says that Yggdrasil is a 21 bit DAC. But the DAC chips that they put in the device ( Analog Devices AD5791BRUZ, 2 per channel) are 20 bit with the error of plus-minus 0.5 LSB.

How can the DAC be 21 bit if the chips are 20 bit? Using two chips per channel does reduce the RMS voltage of the noise by  a square root of 2. But how can you get to 21 bit from there?

Can someone please explain.
defiantboomerang
@defiantboomerang / @shadorne 

Frankly, I'm interested, care about, etc. both measured performance and the sound. But as I've mentioned and am experiencing first hand (not to mention second hand by listening to other systems), I already have four DACs in total, but discounting the USB DAC in my M6si, that leaves two delta sigma (one in ERC-3 another in UDP-205) and the multibit in the Yggy.  They all sound great and none of them play a fourth verse in a song that only has three. So should I be led to believe that there is in fact a "nirvana dac" that measures perfectly and sounds perfectly so I can hear this fourth verse?
@gdhal 

Try the Benchmark DAC3. Nothing comes close. It will not give the fourth verse, but it will play your music better than anything else out there.

About all of your DACs sounding great -- of course they do. Nobody can tell decent modern DACs apart in a blind test. All perceived differences are just due to placebo.
"Nothing comes close."
Implicit: "...because, I’ve heard ALL the others and speak from first hand experience. "

"All perceived differences are just due to placebo."
Does that apply to the Benchmark DAC3 as well?
@defiantboomerang

I had given the Benchmark DAC 3 serious consideration. I talked at length with one of their sales rep, and I very much liked the fact that he spent the time with me. Something Schiit really doesn't do.

If I recall (and this was months ago so I'm going on memory only), for one thing the DAC 3 uses a Sabre chip 9028 whereas my Oppo uses the 9038. Granted, we all know there is more to the sound than *just* the chip (i.e. analog stage, etc.). Regardless, I just couldn't get past the fact that the Sabre chip in the Benchmark would sound like my Oppo, which uses an even more advanced chip.

Further, the DAC 3 has many "cousin" configurations in their lineup, neither of which zeroed in on the specific (and only specific) functions I was seeking - namely bit perfect PCM conversion. I couldn't care less about the headphone amp, home theater bypass and other features in the DAC 3 that I don't need/want. And because the Benchmark isn't really any less expensive than the Yggy,  it seems to me the cost is spread all that much thinner across all of its functions. So it's PCM specific abilities should be inferior to the Yggdrasil, because the Yggy's design focus is just PCM.

Unfortunately I had no way of listening to either one prior to purchasing, so the return policy of each was also something I considered.

Still, I think I made the wiser choice in my particular case to go with the Yggy.
@ghosthouse

"Nothing comes close."
Implicit: "...because, I’ve heard ALL the others and speak from first hand experience. "

No, nothing comes close to their technological expertise. DAC3 measures better than anything out there -- hence, nothing comes close.

"All perceived differences are just due to placebo."
Does that apply to the Benchmark DAC3 as well?

Of course it does. Tough, I will buy it, when I save some more money. Not because I think it will sound better than what I have, but because I like technically advanced devices. As regards its sound, the placebo effect for subjectivist audiophiles should/will come from the reviews that praise it. For example, the Stereophile says that DAC3 delivers "ASTONISHING FIDELITY AND EMOTIONAL EXPRESSIVENESS".