Non-Oversampling (NOS) vs,


I am curious. Is a Non-Oversampling (NOS) DAC sound better than a DAC that upsamples the original signal? Or, in other words, is it better to maintain the “original signal” and not add mathematical calculated extra bits?

I also understand that a DAC’s implementation makes a huge different in the resulting sound quality and so does the analog section. I am just trying to better understand a NOS DAC vs one that upsamples.



hgeifman
My only experience with upsampling DACs is a Benchmark DAC3 and a Chord MOJO.

With both I prefer the upsampled sound from redbook sources. 

Maybe it's placebo but I hear more detail with upsampling through these DACs.
An upsampling and filtered DAC will measure much better on paper. That's indisputable.

My experience is that either type can sound good, however, my non-oversampling, filterless DAC sounds more like analog - less fatiguing and less "glare" at the sacrifice of some detail.


Depends, converting redbook the 2R2 Multibit Holo Spring dac, sounds far better on NOS than it does with OS, and you find that goes for most R2R Multibit dacs that can do it.
I'm not into Delta Sigma dacs "trying" to redbook so I won't comment on those.

Cheers George

OP>
I am just trying to better understand a NOS DAC vs one that upsamples.

I’m wondering myself how great a part this plays in the final result?

I mean after all, does this really matter somehow?

I believe regardless a dAC be an OS or NOS DAC, there is more to this than the philosophy or approach being lent to the solution.

like the OP alludeed to, as such, EVERYTHING in the dAC build and implementation has to be considered as a ‘WHOLE’, despite the OS or NOS digital side of the affair.

as I understand OS DACs some sonic aberations are attenuated or ameliorated outright via up sampling the rate. the other approach handles things differently, of course.

then to, some dACs deal with sonic issues on the analog side.

doesn't that all by itself sort of make the design argument nonessential?

for eX… lets say you got to hear similarly priced but not exactly, two dACs. one of each design, and in your own rig.

in the end, things were close. very very close. its come down to a coin toss.

the thing then is cost. Right?

one must stay focused on the overall, or end result and not merely at which way they went to achieve it.

it do make for some interesting debates though, from time to time.

if the dAC has the short list of options I desire, I can afford to buy it, and its a decided boost to the sQ in the system, I could care less if they got blind squirrels juggling knives while jogging on a treadmill inside the thing.

well, so long as I don’t have to feed or clean up after them, and they maintain their hygiene.
Upsampling allows mathematical filtering which is more accurate than anything in the analog domain. It also tends to randomize differential non-linearity from physical devices.

Anything built in the real world will suffer from differential non-linearity. This occurs in both time (jitter) or in amplitude. (True whatever your DAC topology)

It is simple physics. Build anything with discrete levels (steps) in time or amplitude then you will have inherent physical limitations in accuracy between adjacent levels (steps). The errors are always there whatever you physically build. So building something with many more than necessary steps (levels) means the errors are far more likely to be smaller, benign, inaudible and random.

It is always better to have a higher bit resolution and higher sample rate than actually needed. This means differential errors are more likely to occur outside the audible range (below the noise floor or at higher than audible frequencies).

Think about it.

What is better?

Errors that are close to or within the audible range (16bit 44.1KHz) or errors that are way outside the audible band and can be filtered out (upsampled or high-resolution)

For these reasons most folks find that mathematical upsampling in Roon or other software can help improve the sound from many DACs. This is because it changes the nature of the physical analog errors that absolutely every DAC suffers from.

Latest DAC Chip design tries to leverage this issue by having a hybrid solution - a mathematical random software selects the actual circuits combined to create the amplitude on every cycle - ensuring that no two adjacent samples ever use the same circuit and thus inherent physical differential non-linearity errors are random.

Random errors are several orders of magnitude better than any noise that correlates to a musical signal.

The most accurate DACs like Benchmark DAC 3 are using this hybrid approach. They are equivalent to a 6 bit R-2R DAC running at a very high sample rate. This approach minimizes BOTH the impact of errors in time (jitter) and signal level (amplitude or bits). This approach measures an order of magnitude better than the very best most expensive R-2R NOS design or the very best 1 bit Delta Sigma or DSD.

If you don’t like the sound of accuracy and prefer a bit of distortion then you are part of a large camp. I like tubes too!!!

The above is just a discussion of pure performance accuracy and does not account for tastes.
I only have one NOS DAC, a MHDT Labs Orchid.  I'm listening to Pink Floyd Wish You Were Here with it as I type this and it sounds glorious.  Out of the many DACs I have, it's the one I chose for the system I listen to with headphones most office.  It's the least "digital" sounding DAC I have, but very detailed and easy to listen to.  I don't really care about the technical aspects of it, I just love the way this one sounds.
I think a good NOS dac does sound better (more natural and lifelike) than an upsampling DAC.
@d2girls : Right on! A clever ploy to get the gullible and neurotic to spend more money! 
There are many DACs that appear to be over-engineered and overpriced, but having been through about 7, I don't see how it can be argued that they don't play an important role in the sound of a system, just as a turntable and  cartridge do in an analog system.
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No it is all about several factors , the dac type and implementation, will have some influence of the sound  but also  the quality of the Word clocks, thePower supplies  , parts quality layout, isolation all 
contribute to the final outcome. I have had many dacs in my day ,
pits not allways the most detailed  that sounds the best.
I had 2 ofSchiits top 2 dacs ,as well as ps audio best , and in my system my Bel Canto Dac was the most musical . In other systems
the other  dacs are better suited .your amp And cabling too dictate the tonal balance and ultimate musicality. Tradeoffs in everything 
nothingis perfect, and-everyone has their own likes and dislikes. 

You cannot compare different DACs such as one that is NOS and another that does OS.  In my DAC, the NOS setting is way more musical, I built it that was for my own preference.  The OS has its benefits also on my DAC.  The soundstage gets wider, you hear more detail and more clarity.  Nothing to me that makes me want to give up the musical (emotional) sound that the NOS provides.  But people who have purchased my DAC prefer more details.  Kid of like the tube vs. SS camps.  As someone else mentioned above, always tradeoffs in this hobby.

Happy Listening.  
Kid of like the tube vs. SS camps. As someone else mentioned above, always tradeoffs in this hobby.

@bigkidz -- I was just about to write the same thing. BTW, what DAC do you make?


You just need to listen to Redbook on a "good" R2R dac/cdp that you switch from NOS to OS while listening on the fly, like you can with the Holo Spring.
NOS is far more enjoyable, it has more body to the mids, it seems to extend both the bass and the highs, you can definitely hear the decay (harmonic structure) of piano and cymbals down into silence far better than you can with OS. OS seems to chop it off, a little like Class-D amps also do for me.

Cheers George
@soix2 - DAC is a DHT (direct heated triode) tube DAC with separate power supply RR2R board, V-Caps & Caddock + Shinkoh resistors.

goole: vujadeaudio
the Denafrips Pontus allows you to change from NOS to OS at the touch of a button.
I do change the setting occasionally but always find myself going back to NOS whether the music is served or streamed.
NOS is the better way to go.From my experience over the years I learnt the best way to achieve the sound I want is to keep things simple,all kind of sound "manipulation" gear maybe genuinely trying to improve the sound but in the end just making thing worst. 
Thanks for these comments.  So, it seems, maybe, NOS is the better way to go.  

What NOS based DAC’s should I look at?  Are there any USA made NOS DAC’s?    Thanks. 
I just settled on NOS for my Denafrips dac. I did spend few weeks testing the difference between the NOS and OS but at the end, I am enjoying the nos better but again the Denafrips is am R2R dac and I am sure it is a matter of taste in music and sound.
I love my Audio Mirror Tubadour III DAC. NOS R2R with tube output stage. Made in USA. $1500 for basic model. $2500 for the SE version. Many of the upgraded parts included in the SE version can be chosen at intermediate cost levels.

Very much agree with the NOS fans.
First time I heard NOS - over a decade ago through a simple Philps-based DAC, I was hooked.
Since then, virtually every oversampling DAC I’ve heard has been subjectively inferior to virtually any NOS DAC I’ve heard.
And I’ve expected to like, and hoped to like, and tried, really, really hard to like and live with some oversampling DACs - only to be very dissapointed.
The fact that OS DACs measure so well yet sound so inferior, at least to me, is COMPELLING evidence that we have yet to figure out how to measure what really matters.

@jordand2 

I agree with evertyhing that you said, and that has been my experience as well, but I wiuld be curious to hear the best offerings from say, dcs and MSB to see how far the best OS DACs are these days. Meanwhile, I'm very happy with my NOS DAC.

What NOS based DAC’s should I look at?  Are there any USA made NOS DAC’s?    Thanks. 
 

Yes Mojo Audio and Audio Note Kits dacs are very good. 

@rodge827 

You should hit up the ol’ search bar for hours (maybe even days) of reading enjoyment! 
There are a Bazillion posts on R2R and NOS on this site and a lot of it is really helpful!

BTW- I use an Aqua La Scala. R2R and NOS and Tubes all the way! 

@analoguefan - Which Denafrips DAC do you have?  The Ares II is always oversampling even in NOS mode based on its measurements. 
 

 

@hgeifman - Check out some of the oversampling videos that Paul from PS Audio has. I found them informative. 

@designsfx 

I own both the Mojo Audio XSE and a highly modified ANK 2.1b Sig. Mojo is USA made and ANK is from Canada and the guy who will build one is in FL. I like both Dacs for how they sound. Prob going to keep the ANK in my main system and the Mojo to the beach house when finished. But that might change hard to decide. 

@rodge827 

I have the same ANK 2.1, just upgraded last year, and I feel lucky every day. Great DAC.

@rodge827 

Send me a note describing your ANK mods- I find the different approaches to these upgrades very interesting!

Have a gustard R26.

Easy to switch back and forth NOS/OS.

prefer NOS.

Just need gustard to get a bit better at docs and customer service.