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  3. 146320-17004

A comparison between two DACs, one R-2R, the other ES 9038-based.

This is an item from the FWIW Department, I guess.

Recently I set up an A/B comparison between a Denafrips Pontus and an OPPO Sonica…. Both DACs fed from a Nuprime CDT-8, via the XLR inputs on the same preamp, and everything else constant through the two signal paths to the speakers.

The result when I repeatedly toggled back and forth from the preamp’s input one [Denafrips] to its input two [OPPO]?---- To my surprise [and disappointment], the sounds from the two DACs were utterly indistinguishable, across all kinds of music, after repeated trials … impossible to tell apart… impossible.

The moral of the story? I don’t really know, but it does suggest to me that those who say that DACs of comparable quality cannot be told apart just might have a point.

I bought both the Pontus and the Sonica because I thought that it would be nice to have on hand DACs of “different flavours,” one based on an R-2R ladder, the other based on a delta-sigma chip. 

I did want the expected difference to be real… just for the fun of it… else why spend the extra money? So, my “confirmation bias” was, if anything, stacked in favour of there being a detectable difference.  

However, the results of a reasonably well controlled comparison [sadly?] did not bear out that expectation. Differently based DACs, 2-R2 vs delta-sigma, may not offer such different flavours as many suggest. Is that claim all much ado about nothing?

Thoughts from members of the Forum?

 

 

 


128x128Ag insider logo xs@2xzimmerma
jond's avatar
jond
5,660 posts
 
zimmerma regarding having the volumes match its not just about having the volume know in the same setting. Dacs can have different outputs one Dac say an 2v output another a 3v in that case the 3v output will sound louder at the same volume setting. You really need a db meter to verify the loudness match.

Also I personally would suggest, if you can, changing up your methodology. What is often more helpful for me is putting a component in my system and listening to it at length weeks or even months. Then switching components listening some more at length and finally going back again. More subtle differences often become more apparent over time. As always just my opinion YMMV.
zimmerma's avatar
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zimmerma OP
102 posts
 
To celander:
  • Thank you for the datum on the Supreme CDT-8 jitter. I'll look into this aspect of my signal chain. 
  • Possibly changing transports or adding re-clocking would be in order. 

To jond:
  • Both DACs in the comparison have the same output voltage, 4v for the XLR outputs, 2v for the RCA. I controlled for that.
  • As for your interesting version of the earlier poster's "leisurely listening" approach, I tried to address that above, by noting that human "auditory memory" is probably not retentive enough to enable a very meaningful A/B comparison of components in a signal path. In my earlier response I referred to my own weak auditory memory, but is was just a weak attempt at false modesty; I really meant all human beings. Psychodynamic studies show that we just cannot remember enough about a sound series we heard as little as a few minutes ago to make accurate comparisons with one we are hearing now. [I'll dig out a study if I can. It's been awhile.]
Again, a general note a thanks to responders. I am finding these comments on my OP very useful.
zimmerma's avatar
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zimmerma OP
102 posts
 
A question for celander:
Where can I find the jitter rate of 190 psec that you quoted for the Nuprime CDT-8?
Thanks....
twoleftears's avatar
twoleftears
5,313 posts
 
I thought this was first posted in a discussion of the CDT-8 over on AudioCircle, but a quick google search doesn't bring it up.
celander's avatar
celander
1,502 posts
 
OP: The CEO of NuPrime (Jason Lim) provided that to me in an email. BTW, I just reviewed that email: it’s 120 psec, not 190 psec. We’ve had a rather spirited back and forth via email about the jitter number and the meaning of their “ultra-low jitter” and “extremely low jitter” language of their marketing materials.

To me, those language snippets mean different values to different folks. For the NuPrime folks, it’s 120 spec. For me, it means <5-10 psec.

The jitter value is measured at their output clock circuit. I have no idea what the jitter output is at the end for a 4 ft. coax digital cable.
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