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?

 

 

 


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OP: I don’t believe I inverted any symbols. NuPrime thinks “ultra or extremely low jitter” means 120 psec. My interpretation of “ultra or extremely low jitter” is less than (<) 5-10 psec. That’s a big difference in jitter levels that affects SQ. Ask Steve Nugent (audioengr). I returned the transport to NuPrime after audition in my system, as it didn’t improve upon the SQ of my CAL Delta transport, which has less than 50 psec of jitter in the digital output stream. 

Whatever is in Jason’s mind of DAC compensating input jitter reclocking circuits is not relevant to marketing a stand alone transport. If he thought it didn’t matter, then why use marketing language regarding the transport’s jitter qualities? He’s trying to sell a given transport. If he wanted to, he could have pointed out any residual jitter could be reclocked by a suitable DAC having an input jitter reclocking circuit. His marketing language doesn’t point that out, however, for obvious reasons (red flags as to the transport having high jitter output). It’s possible that jitter is lowest via his transport I2S bus. But that is not really clear from his marketing materials, and his report of jitter values at the clock output circuit pretty much dictates jitter output for all digital outputs regardless of formats.

I’m not here to argue about a particular DAC’s input receiver having special associated reclocking circuitry. I merely pointed out that the Pontus DAC lacks the front end digital signal processing of Denafrips Venus and Terminator DAC’s. And that is why one pays a lot more for the top tiers of the Denafrips DAC line.

To celander:
  • I take your point about "compensating input jitter reclocking circuits." No marketeer of a stand-alone transport should rely on that point. "Stand-alone" means stands-alone, after all. 
  • I gather that your "back and forth" with Mr Lim was about the acal measurement of the jitter output of their CDT-8.... Yes?
  • You are quite correct about the difference between the anti-jitter capabilities of the Pontus, on the one hand, and of of the Venus and Terminator, on the other... Femto clock in the latter, not in the former. When I bought the Pontus I did know that.... but a budget is a budget.
Huge +1 to @celander -- especially if both DACs don't have very good reclocking built in.  It's pretty doubtful there is NO difference in sonic reproduction between these two DACs, so the question is why?  I agree with @celander that if you feed two DACs without a very good reclocker crap, you're gonna hear crap.  Whatever way you end up going, you might want to invest in an Emprical Audio Offramp to take jitter out of the equation.  
OP: I’m not going to go into depth of the banter between Jason and me other than to say he felt jitter at 120 psec was “low” although he suspected it was nevertheless inaudible. I disagreed with him, holding the position that jitter at any level above 10 psec was audible in terms of absolute SQ.

Steve Nugent and a parade of others agree with my view. The Jay’s Audio transport when inserted into my system confirmed this view for me.
I'm interested in the LAB 12 DAC SE.  Can anyone confirm if it has changed in any meaningful way since it was first produced in 2013?