[Soundsgoodtome]

"The 'issue' of NOS used to be documented as the stepped wave form, as though by up sampling it could 'fill in the gaps'. This has since been pretty much proved to be nonsense."

astrostar59 do you know where I can read more on this? What did they figure as to why this sounds fine when sent to analogue? Or did the analog stage connect the stepped to form a proper wave?

 

[astrostar59]

I think the next level in DAC sound quality is bit perfect R2R Discrete Ladder like TotalDAC. It does away with the chip and any issues of that. I have it on good authority (in the trade techs that are designing discrete boards at the moment) that a well designed ladder board (chip less) can outperform any chip on the market and also mange bit perfect hi-res as well. Plus there is the possibility to output enough current to not need complex I/V conversion and gain stages. I have not heard one yet, as have an Audio Note DAC 5 which uses the old NOS AD1865 chip.
 
This is the exciting area to me in DAC dev over the last few years. I am not convinced DS chips have moved on much.
 
Then there is FPGA software that uses no chip and no resistors either (Chord and dCS). I haven't heard these either but they seem to have their fan base.

 

[BassDigger]

  I think the next level in DAC sound quality is bit perfect R2R Discrete Ladder like TotalDAC. It does away with the chip and any issues of that. I have it on good authority (in the trade techs that are designing discrete boards at the moment) that a well designed ladder board (chip less) can outperform any chip on the market and also mange bit perfect hi-res as well. Plus there is the possibility to output enough current to not need complex I/V conversion and gain stages. I have not heard one yet, as have an Audio Note DAC 5 which uses the old NOS AD1865 chip.
 
This is the exciting area to me in DAC dev over the last few years. I am not convinced DS chips have moved on much.
 
Then there is FPGA software that uses no chip and no resistors either (Chord and dCS). I haven't heard these either but they seem to have their fan base.

 
I think that I've read NOS described, as such, a few times. As I (mis)understand it, the dac chip, and the oversampling chip, (circuit, or whatever) are two different things. The dac can be used with, or without, OS. The dac chip designer may have an OS application in mind. But in the end, it's the dac designer's choice. So, to say that it's a 'NOS chip' could be a little confusing.
 
It is exciting to read that, perhaps, after stagnating for decades, at last, R2R is moving on! It should do; their have surely been significant advances in manufacturing techniques, since the early ninties, that enable superior designs to be produced. There just hasn't been the demand. We need to spread the word.....more!

 

[Articnoise]

   
I think that I've read NOS described, as such, a few times. As I (mis)understand it, the dac chip, and the oversampling chip, (circuit, or whatever) are two different things. The dac can be used with, or without, OS. The dac chip designer may have an OS application in mind. But in the end, it's the dac designer's choice. So, to say that it's a 'NOS chip' could be a little confusing.
 
It is exciting to read that, perhaps, after stagnating for decades, at last, R2R is moving on! It should do; their have surely been significant advances in manufacturing techniques, since the early ninties, that enable superior designs to be produced. There just hasn't been the demand. We need to spread the word.....more!

 

R2R chips like the BB 1704 are NOS and you have to use an FPGA or DSP software if you want to do OS. The FPGA or DSP software are not only used for OS it also used for digital filtering. Some NOS DACs use a FPGA or DSP software only to filtering, but doesn’t use it for OS.

 

All DACs use filters in some way to take away bi-products (artifacts) from the digital to analogue process. Most use both digital and an analogue filters, but a few NOS DACs like Audio Note are only using the output transformers as analogue filters (out of audio band = out of hearing philosophy).

 

IMO the biggest strength of the NOS design is that no/less digital filtering is needed. Less filtering is “often” heard as more natural sounding. Well it has been so for many years, but as more and more manufacturer have start to make better and more advanced digital filters the sound from well-made OS DACs has gotten much better and more natural sounding IME. 

 

[BassDigger]

 

R2R chips like the BB 1704 are NOS and you have to use an FPGA or DSP software if you want to do OS. ...

 
I don't want any trouble

...., but it's just that my understanding is that all dac chips, at least the r2r ones that I'm familiar with, are 'NOS'; if you want to describe it in that way. So, what's the point in mentioning it? It's the dac; the filtering architecture that's used within the dac unit (in addition to the dac chip), that can include OS.
 
The "This is a 'NOS chip'." description implies that there are 'OS chips'; dac chips with OS built into them. If there are, I'm afraid that I'm just unaware of them. That's all.

 

[astrostar59]

   
I think that I've read NOS described, as such, a few times. As I (mis)understand it, the dac chip, and the oversampling chip, (circuit, or whatever) are two different things. The dac can be used with, or without, OS. The dac chip designer may have an OS application in mind. But in the end, it's the dac designer's choice. So, to say that it's a 'NOS chip' could be a little confusing.
 
It is exciting to read that, perhaps, after stagnating for decades, at last, R2R is moving on! It should do; their have surely been significant advances in manufacturing techniques, since the early ninties, that enable superior designs to be produced. There just hasn't been the demand. We need to spread the word.....more!

Not sure on the chip advancements. Many NOS manufacturers say the early and harder to sure chips are still the best (AD1865 for example).
 
I am unaware of any of the big chip producers making specific NOS chips. It seems industrial chip applications are being adapted to audio?
 
R2R is more expensive to produce, and DS can bet as cheap as chips (pun intended). But to complicate the subject we had FPGA and discrete boards as well now, so more going on than ever. Plus some non oversampling DACs uses 8 chips to gain the required resolution for 192+.
 
I think the attraction of R2R to me is the lack of messing with the signal, it seems the less it is modified the better it sounds.

 

[BassDigger]

  Not sure on the chip advancements. Many NOS manufacturers say the early and harder to sure chips are still the best (AD1865 for example).
 
I am unaware of any of the big chip producers making specific NOS chips. It seems industrial chip applications are being adapted to audio?
 
R2R is more expensive to produce, and DS can bet as cheap as chips (pun intended). But to complicate the subject we had FPGA and discrete boards as well now, so more going on than ever. Plus some non oversampling DACs uses 8 chips to gain the required resolution for 192+.
 
I think the attraction of R2R to me is the lack of messing with the signal, it seems the less it is modified the better it sounds.

 
No, I don't think that there are any new audio R2R chips being made; that would be really big news! (i.e. I think that the chips that Schiit use are military designs.) I was just referring to better manufacturing techniques, new tech, that enables good discrete R2R circuits to be made, and made more cheaply.
BTW. I don't even know what FPGA is.
 
(I'm trying to give up this pedanticisation,.... but i'm not sure if I'm getting across) it looks to me like the differentiation between NOS and OS is the same as the identification between R2R and DS.
This can get confusing, because most R2R dacs (the whole audio section/unit) include OS. Or, in the context of this thread, even though all R2R chips are NOS, they can still be used in a DAC (unit) with an OS filter (an additional component).
So, what would you call this? It's got a "NOS chip", but it's an OS DAC. Isn't that contradictory? 
 
"Plus some non oversampling DACs uses 8 chips to gain the required resolution for 192+" (sorry to be quoting).
Whether the DAC (unit) is OS or NOS, is probably irrelevant; the OS happens separately from the chip; it's a separate process from the DA conversion.
I think that you mean "...some R2R DACs....". Even though all NOS DAC units may use R2R chips, it doesn't mean that all R2R DACs are NOS. 
 
I wonder if the confusion is because the process of DS conversion may be like OS. So, perhaps the DS chips are thought of as the 'OS chips'. But, who's interested in those?

 

[astrostar59]

I was referring to some high end DACs that double up the same chip, or 4 or 8 to game the required resolution. For example the PCM1704 is 24bit 96K and by adding 4 or 8 of them you can go higher (at 24 bit).
 
http://www.alldatasheet.com/datasheet-pdf/pdf/56818/BURR-BROWN/PCM1704.html
 
As far as I understand it many DS chips do oversampling in the chip and some even the filtering (though not all). I am wondering if we should be even calling DACs with NOS chips R2R at all, isn't R2R the method of converting to digital stream to voltage using lots of laser trimmed resistors? i.e. no chip used at all?
 
Someone else needs to chime in.... But building a true ladder digital board which is chip less is probably the most expensive way to make any DAC work, and the manufacturers going that route must be convinced of the sonic merits.
 
But going back to the theory of why non oversampling designs may sound 'different' is the ability to play at bit perfect RedBook and drop the (often crude) filtering found in other designs.
 
There are other routes as seen in MSB DACs that are both a discrete design but also oversample and then apply a filter after (like DS).

 

[BassDigger]

^...still thinking about this...and still trying to get to my point, without waffling. 

 
This is the R2R thread. No R2R chips include oversampling (as far as I'm aware). In the world of R2R, an OS chip is another chip that does the oversampling, like the SA7220 (Philips), and CDX1088 (Sony).
So, to say that a dac chip, like the PCM63, is a non-oversampling chip, is a bit 'stating the obvious'! Or, it could be seen as implying that it's a chip that cannot be used in conjunction with OS, which would just be misleading.
 
So please, let's just call them R2R chips; the oversampling (NOS, or OS) is a different component, and a different topic.
 
Waffle over. 

 

 

[BassDigger]

....
 
As far as I understand it many DS chips do oversampling in the chip and some even the filtering (though not all). I am wondering of we should be even calling DACs with NOS chips R2R at all, isn't R2R the method of converting to digital stream to voltage using lots of laser trimmed resistors? i.e. no chip used at all?
 
Someone else needs to chime in.... But building a true ladder digital board which is chip less is probably the most expensive way to make any DAC work, and the manufacturers going that route must be convinced of the sonic merits.

 
Yeah, I used to know them as 'multibit', but now that term can also include DS.
 
What should we call them? Anybody?!?
 
I've decided that listening to 'them?', is more fun than talking about 'them?'! 
 
I guess the demand has got to be there, for companies to make 'true ladder' dacs. And for demand to increase, awareness, of what people are missing, has to, also.
We're getting there; more and more people are talking about.....whatever we should call them. And some manufacturers are introducing 'multibit' and even NOS multibit DACs.

 

[astrostar59]

   
And some manufacturers are introducing 'multibit' and even NOS multibit DACs.

I think you are correct. The PCM1704 for example can do 8x oversampling but also do R-2R non oversampling. It is a popular chip for DIY NOS builds.
 
After having had various mid budget (10K) DACs over the years and some R-2R DAC more recently I think the mid market R-2R DACs are offering superb sound quality on Redbook. Yes there are upper tier DACs with multiple chips but I am not sure the gains are as big as they used to be. As long as the DAC used has a good power supply and quality gain stage (decent amplifier stage) a fantastic level of performance is possible.
 
DACs I would rate are Lampizator, Audio Note (inc the kits), TotalDAC.

 

[BassDigger]

  I think you are correct. The PCM1704 for example can do 8x oversampling but also do R-2R non oversampling. It is a popular chip for DIY NOS builds.
 
.....
 
DACs I would rate are Lampizator, Audio Note (inc the kits), TotalDAC.

 
Aahahaa! (wiggles eyebrows) 

 What you mean is that the PCM1704 R2R (or whatever we're supposed to call them) chip can be used in both oversampling and non-oversampling DACs. 

 
I envy your 'experience'! How much of your listening is redbook?

 

[astrostar59]

   
Aahahaa! (wiggles eyebrows) 

 What you mean is that the PCM1704 R2R (or whatever we're supposed to call them) chip can be used in both oversampling and non-oversampling DACs. 

 
I envy your 'experience'! How much of your listening is redbook?

Yes PCM1704 can be both NOS or OS. 95% Redbook. I have a splattering of higher res but the cost and availability has not got me involved much, though I have heard many top DS DACs with 'high res'. DSD however may change that, in a Lampi it did sound superb. But how many recordings available as DSD?

 

[Luckbad]

Back to vintage DAC talk?

Does anyone have preferred chips?

I think my favorite is Ultra Analog D20400A, followed by Analog Devices AD1862N-J then Burr Brown PCM1704U-K.

 

[Articnoise]

   
I don't want any trouble

...., but it's just that my understanding is that all dac chips, at least the r2r ones that I'm familiar with, are 'NOS'; if you want to describe it in that way. So, what's the point in mentioning it? It's the dac; the filtering architecture that's used within the dac unit (in addition to the dac chip), that can include OS.
 
The "This is a 'NOS chip'." description implies that there are 'OS chips'; dac chips with OS built into them. If there are, I'm afraid that I'm just unaware of them. That's all.

 

My point was that if you chose NOS you have to filter one type of artifacts and with OS some other types of artifacts, so different requirement for the filtering section. With some new better digital filters the sound from OS has got much better and the sound more fluid and organic. Those characteristics has in the past been the biggest advantage of NOS over OS IME.

 

IIRC Schiit’s multibit chips are not R2R.... I don’t think it matter thou.  

 

Yes DS chips do oversampling or at least upsampling in the chip and some even the filtering. Some R2R chip do OS too, most not.