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
I would hazard a guess that for several reasons (only 20 bit, R2R and no upsampling), by necessity the filtering in this DAC will be close to Nyquist and therefore quite aggressive or sharp (like Non upsampling CD players). I suspect it is this smoother sound from filtered highs and the fantastic analog section that makes this DAC so musical and desirable to some folks over competing ESS 9018 and 9028 style DACs.

Measurements only validate accuracy or high fidelity capability of a device. The musicality aspects are all in the ear of the beholder.
@shadorne 

You are correct that measurements only validate accuracy or high fidelity capability of a device. The musicality aspects are all in the ear of the beholder.

In my case, there is something else noteworthy.

I already have a "virtual" Benchmark DAC 3. I call it an "Oppo UDP-205". It, has a MEASURABLY BETTER AND MORE ADVANCED DAC chip than the Benchmark.

Some folks might now write back and cry foul; reminding me that the DAC chip itself represents only 20 percent of the story, and that the implementation of said chip, analog stage and grace of God comprises the remaining 80.

I will then write back and point out that because the Oppo uses a Sabre ESS9038 instead of an ESS9028, that my 20 percent should really equate to 30 percent.

And away we go.

@gdhal 
 
The Oppo UDP 205 is indeed outstanding and I expect that it sounds a bit brighter and thinner than the Yggy. It may well outperform the DAC3 as you claim. Perhaps the Oppo UDP 205 will be another Class A or A+ Stereophile recommended player. Per JA above, we can easily surmise why the Yggy is not.
@gdhal 

I'll up-the-anti. I'd like to suggest for the moment that you forget entirely about measurements. I don't care if its voodoo. The Yggy sounds spectacular. Please read my last post in the New Yggdrasil - First (and second) Impressions thread.

With respect, bro -- this thread started as a simple technical question and we have more or less arrived at an answer. Let's try to keep it technical.

FYI -- I have asked the manufacturer AGAIN about the 21-20 bit issue. Let's hope that this time they will answer.

I am very happy that you are satisfied with your Yggy. I don't share you enthusiasm and will never buy anything made by Schiit. But despite our differing shopping preferences, we can still have a reasoned technical debate about the 21 vs 20 bit question -- as long as we stay technical.
@defiantboomerang

Apologies.

I sincerely thought a wide degree of latitude would be acceptable, because your post (thread title) is specific to Schiit Yggdrasil, and it has been compared within this thread by others - directly and/or indirectly - to the Benchmark DAC 3. So, by extension, I thought - again, apologies because perhaps my thinking is incorrect - that since the DAC 3 uses a Sabre ESS 9028 chip, it would be reasonable to submit the Oppo UDP-205 into the discussion, because it too uses an Sabre ESS chip, albeit a 9038.

Please let us know what you ultimately decide to "shop" for.