Topping Centaurus R2R DAC Review

[NTTY]

I had a Denon DVD-A1 in the past which had two PCM1702 per channel (for the main stereo channels). No manual trimming on these as opposed to the PCM58 or PCM64.
It had very good performances. Unfortunately my measurement interface was the limiting factor at the time. I gave the player to my brother who does not know where he’s put it and so I could not measure it again.
EDIT: I forgot that I still have a Denon S10 with 2 BB 1702 per channel. I’ll grab it if time allows.

 

[welwynnick]

Perhaps Amir could loan one of his Levinson DACs to the measurement party? I think he has a No. 360S?

He tested it a few years ago. It did reasonably well considering.

Mark Levinson No 360S DAC Review

This is a review and detailed measurements of my Mark Levinson No. 360S DAC. I purchased it sometime around 1999 when the new high resolution formats had come out (DVD-A and SACD). It has been a solid foundation of countless audio evaluations I have performed near two decades now. The 360S...

www.audiosciencereview.com

 

[NTTY]

Hi everyone,

I played again with my big Denon as it offers trimming pots for the MSB adjustment of their BB PCM58-K DACs. BurrBrown offered up to 4 pots to adjust 4 bits, but the Denon has only two. The feature is undocumented in the Denon's service manual and there's no detailed schema provided either. So I didn't know what these two trimming pots would adjust but I assumed THD at full scale. It was epic to get there as the main board is below the servo board and this adjustment must be done live, with signal.

Anyways, I managed to improve the distorsion of the Denon by a massive 8dB! And so it beats the Centaurus in THD

Here below is the results with an undithered 999.91Hz sine tone @-6dBFS:

The red trace is the one of the Denon (PCM58K) and the green one behind is that of the Centaurus. You can see the harmonic distortion which is indeed a little higher.

Of course, all of that is at 16bits/44.1kHz, and the Centaurus can process 24bits which the old BB PCM58 can't.

Cheers

 

[Jimster480]

Interesting but expensive

 

[AdamFrandsen]

Now I would like a review of the Schiit DAC with the TI R2R chip to compare... The reason is if it should start to drift changing two R2R DAC chips os easier than trying to replace a whole resistor ladder. I know there was a review of the Schiit with another chip, but not the TI b version...

 

[MaxwellsEq]

Hi everyone,

I played again with my big Denon as it offers trimming pots for the MSB adjustment of their BB PCM58 DACs. BurrBrown offered up to 4 pots to adjust 4 bits, but the Denon has only two. The feature is undocumented in the Denon's service manual and there's no detailed schema provided either. So I didn't know what these two trimming pots would adjust but I assumed THD at full scale. It was epic to get there as the main board is below the servo board and this adjustment must be done live, with signal.

Anyways, I managed to improve the distorsion of the Denon by a massive 8dB! And so it beats the Centaurus in THD

Here below is the results with an undithered 999.91Hz sine tone @-6dBFS:

View attachment 416780

The red trace is the one of the Denon (PCM58) and the green one behind is that of the Centaurus. You can see the harmonic distortion which is indeed a little higher.

Of course, all of that is at 16bits/44.1kHz, and the Centaurus can process 24bits which the old BB PCM58 can't.

Cheers

Do you realize that you have invented a new class of audio tweakery?

 

[AdamFrandsen]

This is the supposed performance of the Schiit using the newest TI R2R chip, again I would love to see it tested here as well! It uses 2 chips per channel, which with meticulous implementation could achieve 21bits of pure R2R... To me the Centaurus looks like it uses 16bit ladders from pictures of the board, but I am no expert in spotting this... Does anyone know if the additional bit depth up to 32bit is achieved by noise shaping and oversampling in the topping or simply truncating the additional bits?

 

[all24bits]

A lot of this group sounds absolutely enraged and personally incensed that this product even exists and that there is a market for it.

Someone even suggested putting time and resources towards a better engineered option (ie, delta sigma) even though all modern Topping DACs are already transparent and solved problems. Like Wat

I'm not sure why we aren't advocating that Topping cease all further development and research since there can be nothing gained at this point in the technology of sound reproduction from DACs.

 

[unpluggged]

I'm not sure why we aren't advocating that Topping cease all further development

Who says "we" aren't? I do. And I'm not the only one here.

 

[SMen]

This is the supposed performance of the Schiit using the newest TI R2R chip, again I would love to see it tested here as well! It uses 2 chips per channel, which with meticulous implementation could achieve 21bits of pure R2R... To me the Centaurus looks like it uses 16bit ladders from pictures of the board, but I am no expert in spotting this... Does anyone know if the additional bit depth up to 32bit is achieved by noise shaping and oversampling in the topping or simply truncating the additional bits?View attachment 416918

From what I can glean it's 4 resistor arrays each for PCM and DSD. I am not sure how that results in a 16 bit ladder for PCM.

 

[all24bits]

Who says "we" aren't? I do. And I'm not the only one here.

OK, so all further development of DACs should cease industry wide then. Which designs should stay in production and Which companies should shut their doors or remain open? How many companies should remain in business and how many companies should turn to different industries? Has Topping been alerted they've served their useful purpose and can go away now?

I'm not being glib. I'm being serious. If all modern DACs are transparent and bring no audible benefits, why are we even still in the hobby and why are these companies who make chipsets and implement them wasting everyone's time and money? Why are we not in another hobby discussing things that actually matter and differ instead of discussing things that are identical regardless of what product is purchased? Serious questions.

 

[unpluggged]

OK, so all further development of DACs should cease industry wide then. Which designs should stay in production and Which companies should shut their doors or remain open? How many companies should remain in business and how many companies should turn to different industries?

No, it's because Topping are incompetent and demonstrate bad engineering. Chasing high performance in measurements, they neglect the basics that constitute the concept of good engineering: safety and reliability, pushing flawed and often unsafe products to market in hopes they will be lucky and the design will turn out to be robust enough to outlast the statutory warranty period, or get away with some damage management measures post-factum, at most. Being located in a jurisdiction with loose enforcement practices, it's been working for them so far.

 

[all24bits]

No, it's because Topping are incompetent and demonstrate bad engineering. Chasing high performance in measurements, they neglect the basics that constitute the concept of good engineering: safety and reliability, pushing flawed and often unsafe products to market in hopes they will be lucky and the design will turn out to be robust enough to outlast the statutory warranty period, or get away with some damage management measures post-factum, at most. Being located in a jurisdiction with loose enforcement practices, it's been working for them so far.

Understood about Topping.

 

[oleg87]

A lot of this group sounds absolutely enraged and personally incensed that this product even exists and that there is a market for it.

Someone even suggested putting time and resources towards a better engineered option (ie, delta sigma) even though all modern Topping DACs are already transparent and solved problems. Like Wat

I'm not sure why we aren't advocating that Topping cease all further development and research since there can be nothing gained at this point in the technology of sound reproduction from DACs.

Where? I haven’t trawled 24 pages of this thread but most people just seem bemused about Topping indulging the DAC implementation detail crowd with a product that underperforms their other stuff.

 

[Killingbeans]

A lot of this group sounds absolutely enraged and personally incensed that this product even exists and that there is a market for it.

Not enraged in any way. But it does seem a bit silly that people keep insisting on spreading the unfounded idea that R2R is somehow "more analogue".

It's hard to keep a straight face... that's all.

Someone even suggested putting time and resources towards a better engineered option (ie, delta sigma) even though all modern Topping DACs are already transparent and solved problems. Like Wat

Makes sense if the non-R2R DAC is significantly cheaper. That would give you more resources to put towards the actual bottlenecks of your system.

But if we assume they both perform "transparent" and cost the same, then yeah. That's just dumb tribalism.

I'm not sure why we aren't advocating that Topping cease all further development and research since there can be nothing gained at this point in the technology of sound reproduction from DACs.

Wouldn't make much of a dent anyway. For most people the hobby gets a great deal of its appeal from romanticism and mysticism, and human nature will make sure it doesn't change any time soon. Topping just fill a demand.

Personally I wouldn't mind if stand alone DACs went the way of the dodo, but that's just me.

 

[boxerfan88]

Really sad to see such sweeping defamatory post about Topping being allowed to stand on ASR.

I didn’t see a single Topping ASR review done by Amir flagging out equipment safety issues, nor bad engineering.

 

[unpluggged]

Really sad to see such sweeping defamatory post about Topping being allowed to stand on ASR.

And I really sad to see flawed and dangerous products being praised and blindly put on a pedestal just for topping measurements. Also look up the definition of defamation and retract your claim, otherwise I will ask the staff to implement respective measures for slandering a fellow member.

I didn’t see a single Topping ASR review done by Amir flagging out equipment safety issues, nor bad engineering.

Because Amir's reviews do not focus on such issues. Amir does not run an electrical safety testing and certification laboratory. This is up to the manufacturer to ensure their products are safe to use and to obtain corresponding certifications, in the absence of which a product is presumed to be unsafe. That's how it works in the civilized parts of the world.

Look around on this forum and in other similar communities, and you'll see that there were and are, in fact, numerous issues. And to understand that there is no safety certifications, you don't need Amir to point it out in his reviews (though sometimes in the past he did point out some obvious flaws, such as the absent contact between the PE pin of the power connector and the chassis, as was the case with most Schiit devices back then). Because if there were, they would be published.

Once again: the burden of proof that the product is properly tested and certified by a recognized body lies within the manufacturer.

 

[AdamFrandsen]

From what I can glean it's 4 resistor arrays each for PCM and DSD. I am not sure how that results in a 16 bit ladder for PCM.

Each resistor pair represents one bit

 

[SMen]

Each resistor pair represents one bit

Yes, so on the reverse side, the PCM side, we should see 2 x 24 resistors - or something is being done with the Altera Max ii to get it from 16 bits to 24 - otherwise it would have to downsample surely, which apparently it does not, which is where it should get technically interesting, but this seems to have been lost in the gloss.

 

[AdamFrandsen]

It's practically impossible to make a 24bit resistor ladder, because the precision needed of the resistors is so insane... That's why Delta/sigma 1bit DACs exist, and then oversample and noise shape for the rest ... 16 pure bits is still superior... Less than 0.000006% tolerance is needed for resistors in 24bit ladder. For 16bit 0.0015% (15 ppm), which is doable. That is why a 20bit R2R chip like the TI used in the Schiit MIB is quite incredible, using two per channel they can achieve 21 pure bits and also error correction... There also aren't any R2R ADC's, as this cannot be done - the equivalent is a SAR ADC, which is never used in recording studios (like LTC2380-24).