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
Curious what, if anything, is wrong with my suggestion to pose the question to Schiit.
Hi Shadorne,

I'm not sure that what I said in my previous post came across clearly.  It amounts to the same thing the OP said, which you've agreed provides 21 bits of resolution, but described and perhaps implemented in a different manner.

What I described is not "balanced where both chips are operating simultaneously and are always on."  And it does in fact double the "number of unique digital values available."

Please re-read my previous post and see if you don't agree.

Best regards,
-- Al
 
@shadorne 

Let me ask you a different question. Is there a publication for rational audio hobbyists? I am getting tired of subjectivist nonsense. 

@almarg 

Yes. I did understand your post.

Glad we both agree that you can't magically get 21 bits from a 20 bit DAC without ADDITIONAL digital control (the extra bit) which then makes the DAC a 21 bit DAC not a 20 bit DAC. If you had added the extra MSB digital logic control explicitly then I would have understood beter what you were driving at. 






Really guys, 20bit-21bit.

Does it really matter, a PCM-1704 is 24bit, and your hard pressed to hear any difference to the almost swap-able (save for the package difference) 20bit PCM-1702 and that’s 4bit difference.

Cheers George