Topping Centaurus R2R DAC Review

[Geert]

Serious question: how do we think that R2R DACs got their audiophile status?

Because for layman R2R is theoretically (intuitively) the most straightforward method to convert digital to analogue, contrary to delta sigma conversion which requires advanced processing. So they see R2R as the most 'pure' approach, and that is what they'll hear (doing sighted listening).

 

[DualTriode]

What about testing the PEQ filter(s) performance?

 

[roog]

R2R had a poor domestic audiophile reputation at the start. The earliest non-oversampling CD players were R2R and critics called them bright, shrill, gritty, glassy, shouty, lacking in bass etc.

Now, according to audiophiles, these bright, gritty DACs are smooth and "analogue". So, "audiophile status" is valueless.

Yes I remember the early CD players, I didn’t buy one but at the time but I recall the general vibe that they weren’t as good as vinyl!

So how did this change? Many early cd players are now sought after.

Edit: I see that Geert has offered a plausible answer to this.

 

[Snafu]

Would be interesting to see PEQ enabled measurements (like whole spectrum max and min) effects to distortion and dynamic range.

 

[Jeromeof]

Would be interesting to see this against the FiiO K11 R2R ( which I think is about the cheapest R2R implementation ) - though FiiO own rated THD+N for the K11 R2R was 0.025%

 

[Haskil]

Serious question: how do we think that R2R DACs got their audiophile status?

The dangerous myth of original purity must be taken into consideration in this craze for R2R which finds its source among audiophiles resistant to digital

PS. And funny thing, it was through a reversal of the situation that we got there...

 

[milosz]

Topping must have gone to great pains in building these, precision of the parts in the resistor network is important to performance of R2R dacs. But, why bother? One can get a "conventional" DAC with even greater linearity for much less money.

I would love to see results of a well-designed double blind listening test to see if ANYONE can actually hear differences between the various high-quality DACs that are available these days. And I wonder if the only DACs which people could discern as sounding different might be the ones with inferior measured performance - i.e., Audio-GD DACs etc. They might introduce enough artifact that some people could hear them as being different, but I wonder if even inferior DACs sound different enough for humans to be able to discriminate. We might not even be able to hear the difference between one of the low-achieving DACs on Amir's ranking and the top-ranking ones.

 

[Sokel]

Topping must have gone to great pains in building these, precision of the parts in the resistor network is important to performance of R2R dacs. B

Holo makes the R2R modules:

 

[SSS]

Development engineers did know already decades back what the limits and problems of R2R DAC are. Mainly resistor accuracy and tolerance along temerature. Next are shortcome of the switches and their tolerances. OK, if somebody like it, why not.

 

[CedarX]

Topping must have gone to great pains in building these, precision of the parts in the resistor network is important to performance of R2R dacs. But, why bother? One can get a "conventional" DAC with even greater linearity for much less money.

Besides the “if it’s what’s audiophiles want, why not offering it?” reason, I still wonder how much of this is driven by the AKM factory fire aftermaths, when OEM’s realized their extreme dependence upon a couple of chip suppliers.

 

[NTTY]

Topping must have gone to great pains in building these, precision of the parts in the resistor network is important to performance of R2R dacs. But, why bother? One can get a "conventional" DAC with even greater linearity for much less money.

I would love to see results of a well-designed double blind listening test to see if ANYONE can actually hear differences between the various high-quality DACs that are available these days. And I wonder if the only DACs which people could discern as sounding different might be the ones with inferior measured performance - i.e., Audio-GD DACs etc. They might introduce enough artifact that some people could hear them as being different, but I wonder if even inferior DACs sound different enough for humans to be able to discriminate. We might not even be able to hear the difference between one of the low-achieving DACs on Amir's ranking and the top-ranking ones.

We did it with several friends and at lot of ancient DACs. We measured them first, then recorded their analog output with high quality interface and listened to the WAV files with Audacity ABX plugin, which provides the p-value at the end of the test.

Even for those DACs that looked broken when measured, we failed to differentiate them.

 

[NTTY]

Development engineers did know already decades back what the limits and problems of R2R DAC are. Mainly resister accuracy and tolerance along temerature. Next are shortcome of the switches and their tolerances. OK, if somebody like it, why not.

Their advantages too, notably the non-dependance to noise shaping which generates more out of band noise.

The lack of linearity was the challenge, but dither was the software solution that saved them. I have 30 years R2R that have no issue representing a -110dBFS test tone with dither. But without, some lose their linearity before -80dBFS.

 

[Scytales]

Their advantages too, notably the non-dependance to noise shaping which generates more out of band noise.

The lack of linearity was the challenge, but dither was the software solution that saved them. I have 30 years R2R that have no issue representing a -110dBFS test tone with dither. But without, some lose their linearity before -80dBFS.

By the way, those interested can check this lecture about ladder DAC, R2R DAC and modern noise-shaped D/A conversion method :

 

[staticV3]

@amirm did you measure Multitone distortion?

 

[mocenigo]

Besides the “if it’s what’s audiophiles want, why not offering it?” reason, I still wonder how much of this is driven by the AKM factory fire aftermaths, when OEM’s realized their extreme dependence upon a couple of chip suppliers.

But there is still quite a bit of choice. AKM is back, ESS never disappeared, Crystal has improved their DACs significantly, and Rohm has entered the market…

I think this has more to do with selling something to the “discrete R2R or else” folks than hedging against a chip manufacturer suddenly disappearing.

 

[peng]

This is one of the best examples of R2R currently. They should just remove the the NOS 2 filter setting altogether for public safety, just like mandatory seatbelts and other regulations pure dunning Kruger territory to be fa filter tinkerer imho .

R2R is usually not this good so kudos for the very real engineering effort , but why ?

Why, really have to ask? To get people sucked in continuously, they have to keep adding new reasons for audibly better sound quality. They can only come up with new, but not always (though may be sometimes, obviously) real reasons because there are usually none.., and not needed, because those things are already transparent enough for most humans. R2R, MQA, BluOS, DragonFry dacs, HDAMs, Class A, high current, toroidal, elliptical, sand cast tranformer, autoformer, expensive interconnects, fully/truly balanced, high DF>1000, DDG (one of NAD's new one) etc.etc..... the list is endless, yet there are always suckers in audio ready, waiting and rushing to suck things in!

 

[NTTY]

By the way, those interested can check this lecture about ladder DAC, R2R DAC and modern noise-shaped D/A conversion method :

Really cool. Thanks for sharing!

 

[antcollinet]

Because for layman R2R is theoretically (intuitively) the most straightforward method to convert digital to analogue, contrary to delta sigma conversion which requires advanced processing. So they see R2R as the most 'pure' approach, and that is what they'll hear (doing sighted listening).

Combined with the fact that many R2R dacs add significant distortion that some people find pleasant. First time I heard one there was a "texture" to the sound that was superficially pleasing. The sound was "thicker". I can't imagine though that it would be something I'd want all the time.

(Sorry - horrible subjective words to use - but I am describing a subjective impression - of course I was also listening sighted, so it is quite possible there was no objective difference at all - however the levels of distortion we've seen measured in some of these are well into the audible range.)

 

[Heulpic]

It would be interesting to know where dCS land in terms of performance in comparison. Is there any billionaire here to send a unit to Amir for testing?

 

[bahamot]

If only holo audio cyan 2 get measured too...