NOS v. OS DACs....

EDS_ · « **on:** 8 Jan 2009, 05:58 am »

What are some pros and cons of each?

Also is anyone aware of a primer regarding DAC terms and operation?

Also II, is Delta Sigma conversion used widely outside of SACD DACs?

wilsynet · « **Reply #1 on:** 8 Jan 2009, 07:24 am »

Oversampling: Very detailed and accurate. High energy, excellent treble extension.

Non-oversampling DACs: Subjectively more natural tone and musical presentation. Entry level implementations tend to have relatively high output impedances, around 2K-3K output Z. Depending on your particular DAC, you may need to be more careful with system matching.

Paper from Ryohei Kusunoki who is regarded as the father of the NOS DAC:

http://www.sakurasystems.com/articles/Kusunoki.html

I'm a NOS DAC fan, but I can certainly understand the flip side of the argument and have owned a number of oversampling DACs in the past.

It's really a preference thing. Your ears will tell you which you prefer.

Big Red Machine · « **Reply #2 on:** 8 Jan 2009, 12:55 pm »

Exactly. I tried an NOS and hated it immediately. Some love them. So definitely a personal choice. (It was too laid back for me.)

PhilNYC · « **Reply #3 on:** 8 Jan 2009, 01:07 pm »

Personally I've not found any real consistency in sound to say a NOS vs OS DAC is "better". Much has to do with the implementation. Here's a pretty good 1-pager discussing the purpose and methods for up/oversampling:

http://www.resolutionaudio.com/papers/Up-Oversampling.pdf

goldlizsts · « **Reply #4 on:** 8 Jan 2009, 01:24 pm »

Quote from: PhilNYC on 8 Jan 2009, 01:07 pm

Personally I've not found any real consistency in sound to say a NOS vs OS DAC is "better". Much has to do with the implementation. Here's a pretty good 1-pager discussing the purpose and methods for up/oversampling:

http://www.resolutionaudio.com/papers/Up-Oversampling.pdf

My case - NOS I find more musical than an OS one. The NOS DAC I have is a Shek d2, which had been played at one of our raves (I was absent from that one). The OS one I have is a Zhaolu 2.5C, modifed with LM4562 opamps and a bypass. I find the OS one on the bland side in "my" system. The original Shek DAC I found to be warm, sweet. Relatively, it seemed that it may lack a little extension at the top (relative? because of the more supple mids?). Now, I have replaced the output caps on the NOS DAC, and the transparency is excellent. However, the tradeoff - lost a little in sweetness. The original caps on the NOS DAC was Siemens; I replaced with Mundorfs. The Zhaolu 2.5C is known for its bigger than life, say, soundstage. The modded NOS one now is also excellent. If I have to choose, NOS for me.

It's probably very true that however the DAC behaves in any system is dependent on the electronics. It's just my "GENERAL" perception that it's on the too-white for me. Again, it's a case of personal taste perhaps.

Shek
(no, I'm not the DAC; it's coincidental that the designer/maker of my DAC is also called Shek, and the DAC has Shek as its brand name.....)

BobM · « **Reply #5 on:** 8 Jan 2009, 01:34 pm »

I find that the type of music played through each DAC can sometimes influence the listener. A simple song of guitar and voice, or perhaps a small chamber ensemble sounds best to me through the NOS DAC. But a high energy jazz or rock group with bigger dynamics, or very complex or dense music needs the OS DAC to pull it all out. The NOS DAC's I've heard tend to choke on overly complex or dynamic music.

So, at least IMO, the type of music you listen to most often may play a role in what you prefer.

Enjoy,
Bob

Crimson · « **Reply #6 on:** 8 Jan 2009, 01:56 pm »

Quote from: PhilNYC on 8 Jan 2009, 01:07 pm

Personally I've not found any real consistency in sound to say a NOS vs OS DAC is "better".

That's my opinion as well. I've used excellent dacs from both camps, and currently have one of each.

PhilNYC · « **Reply #7 on:** 8 Jan 2009, 02:19 pm »

Quote from: BobM on 8 Jan 2009, 01:34 pm

I find that the type of music played through each DAC can sometimes influence the listener. A simple song of guitar and voice, or perhaps a small chamber ensemble sounds best to me through the NOS DAC. But a high energy jazz or rock group with bigger dynamics, or very complex or dense music needs the OS DAC to pull it all out. The NOS DAC's I've heard tend to choke on overly complex or dynamic music.

So, at least IMO, the type of music you listen to most often may play a role in what you prefer.

Enjoy,
Bob

I don't know if there's anything inherent in OS vs. NOS that would cause this. Maybe the NOS DACs that you've heard have a less-sophisticated analog stage that chokes on the complex/dynamic stuff? I'd be curious to know which DACs in each camp led you to this conclusion....

The main purpose of OS is to elevate the digital artifacts created in the D-A process to a higher frequency and facilitate the filtering of those artifacts (compared to NOS, where those digital artifacts sit right on the edge of the audible frequency spectrum, so filtering them might have more of an effect on the actual audible sound).

CSI · « **Reply #8 on:** 8 Jan 2009, 02:20 pm »

I too have had good examples of both. I was happy with my OS Bel Canto for years until I bought my CIA NOS DAC. I thought the CIA was more "musical" and a big improvement but part of this could have been newer technology, chips etc. or just implementation. I think the basic differences are audible to everyone with the OS types offering more dynamics and treble liveliness with some music. It is always a trade off. Like an old hunter I know likes to say, "You can never get all the fat coons up one tree".

BobM · « **Reply #9 on:** 8 Jan 2009, 02:24 pm »

I've tried the Monica II, that I owned for a while, and a few other NOS's that were brought over for me to listen to (I forget the names). In each case they were wonderful on simple stuff but not able to handle more complex or "big" music. They didn't compress as much as break up and muddy things.

For the most part the analogue stages were very simple - caps direct out to the RCA's. Could be the problem, but I didn't hear the same breakup with non-NOS DAC's using this same simple analogue stage (i.e. Samsung or Technic's DVD/CD/SACD players that I modified some years ago). So I tend to think it's a natural characteristic of the DAC itself. Now I haven't really compared against those NOS DAC's that stack multiple DAC chips for a more refined sound. That might improve on the resolution over single NOS DAC chips. Don't know.

Bob

goldlizsts · « **Reply #10 on:** 8 Jan 2009, 03:17 pm »

Quote from: BobM on 8 Jan 2009, 02:24 pm

I've tried the Monica II, that I owned for a while, and a few other NOS's that were brought over for me to listen to (I forget the names). In each case they were wonderful on simple stuff but not able to handle more complex or "big" music. They didn't compress as much as break up and muddy things.

For the most part the analogue stages were very simple - caps direct out to the RCA's. Could be the problem, but I didn't hear the same breakup with non-NOS DAC's using this same simple analogue stage (i.e. Samsung or Technic's DVD/CD/SACD players that I modified some years ago). So I tend to think it's a natural characteristic of the DAC itself. Now I haven't really compared against those NOS DAC's that stack multiple DAC chips for a more refined sound. That might improve on the resolution over single NOS DAC chips. Don't know.

Bob

Hmmmm, I had been wondering at times in the past, when I set the volume at like 12, 1 o'clock position (normally 11 would be comfy), I began to dislike the sound (mostly orchestral). SO that's why (what do I know?!) perhaps. I was blaming the boxes. You live and learn. Because of the ignorance, I didn't do same with the OS Zhaolu though. Would be enlightening. So, I'll just have to limit myself to elevator music........

GeorgeHudetz · « **Reply #11 on:** 9 Jan 2009, 02:52 am »

I have a Perpetual Technologies P-3A (with Modwright Level II mods), which by default upsamples to 24 bit, 96 kHz, but the upsampling can be disabled. This thread encouraged me to do a quick study, something I always wanted to do but never got around to - I've usually just left it in NOS mode.

With Diana Krall, Live In Paris, set to repeat the same 20 second sequence in track 3, I toggled back and forth, with and without upsampling. After a few back-and-forths, it became clear that the non-upsampled playback was a little clearer and a touch more dynamic. The upsampled seemed to have a thin veil, but was perhaps a bit smoother. On a good recording like this, I prefer the non-upsampled. But, I could see upsampled being better for a poorer quality recording that I would want to play loud, like old Led Zeppelin or something. I guess I'm lucky to be able to switch between the two.

My .02,

George

nicksgem10s · « **Reply #12 on:** 9 Jan 2009, 03:19 am »

I currently own both and have owned multiple in both category.

I have heard both sound incredibly good in my own and in other systems.

The NOS dac I currently have is a DIY Paradise Monica USB taken to the absolute extreme with modifications and ultra high quality parts as well as running on a very high quality sealed lead acid battery. This replaced an Altmann Attraction dac in my system. It has a superb relaxed quality about it and an absolute silent black background.

The OS dac I own is the new ASi B-USB dac I just purchased recently. I have owned a bunch of different dacs & cd players and listened to a ton more.
This new B-USB dac is simply as good as it gets to my ears. This is even when comparing to some of the highest rated digital sources that cost more than many new cars and even some homes

I think you have to hear well implemented designs of each and give them some time as the presentation of NOS vs OS can is very different in my experience. Had I not heard my new ASi B-USB dac I would have lived happily with my Monica USB that is modified.

TheChairGuy · « **Reply #13 on:** 9 Jan 2009, 03:26 am »

Quote from: BobM on 8 Jan 2009, 02:24 pm

I've tried the Monica II, that I owned for a while, and a few other NOS's that were brought over for me to listen to (I forget the names). In each case they were wonderful on simple stuff but not able to handle more complex or "big" music. They didn't compress as much as break up and muddy things.

Bob

That's exactly where I've been stuck with NOS units....it does simple, but not complex music, right.

Not sure if it was compression, break-up, muddy or distortion....it just didn't sound right (to me)

John

wilsynet · « **Reply #14 on:** 9 Jan 2009, 05:00 am »

Quote from: GeorgeHudetz on 9 Jan 2009, 02:52 am

I have a Perpetual Technologies P-3A (with Modwright Level II mods), which by default upsamples to 24 bit, 96 kHz, but the upsampling can be disabled. This thread encouraged me to do a quick study, something I always wanted to do but never got around to - I've usually just left it in NOS mode.

There's a difference between oversampling and upsampling. You can switch off the upsampling in the P-3A, but I believe it still oversamples and that you don't have a NOS DAC. I thought the same was true of the CIA DAC.

wilsynet · « **Reply #15 on:** 9 Jan 2009, 03:12 pm »

I've had no such problems regarding complex music with my Isabella. Is it output stage related? If we go to higher end examples like Wavelength and Red Wine, do you have the same concerns?

EDS_ · « **Reply #16 on:** 9 Jan 2009, 04:41 pm »

Hey guys,
I have a Musical Fidelity X-DAC V-8 that I like very much. It has 3 coax digital inputs, and one USB "B" input as well plus one digital coax output that is a loop out only from the other digital coax inputs - meaning I do not believe the unit converts USB into coax output. The manual is a trifle ambiguous on this point and I'm going to test to see if USB is converted to coax out in a bit using a modified Scott Nixon DAC that is on hand.

Back on point, my MF DAC converts to 24 bit word length and over-samples 8x. It also up-samples to 192 kHz. None of this is defeat-able.

As I listen to a lot of older "cool" jazz, bebop and some simple classical - I'd like to find a NOS DAC for $400-$600 that.......

A. Inputs USB, coax and optical if possible
2. Can accept input signals above 16/44.1 (not really important)
D. Is not too big
5. An up and oversampling DAC that allows defeat of these features might work too
@. Tubes or no tubes are OK I have a tube amp

Thanks for all the hand holding!

pardales · « **Reply #17 on:** 9 Jan 2009, 04:45 pm »

I do not agree with the suggestion that NOS DAC's can't play complex music. I think that has more to do with overall implementation (digital, analog output, power supply) than anything else. One has to consider overall implementation when looking at DAC's as there is more to it than just the digital techonology (chips, filtering, etc.).

Also, it is possible that NOS vs. OS is too dichotomous. I believe there are DAC's that perform oversampling but not upsampling and that there is a difference between these two techniques.

Scott F. · « **Reply #18 on:** 9 Jan 2009, 07:03 pm »

Guys,

When it comes to NOS vs U/OS designs in DACs there are a few things you need to take into consideration before you take the plunge with either.

First is your overall system 'sound'. If you have a relaxed sounding system, there is a strong chance that your system will sound best with an U/OS DAC. It will provide the detail to make your system sound 'balanced'.

If you have a forward sounding system, there is a strong chance that a NOS DAC will bring the proper balance to make it sound great.

If you've got a mixed system [bright speakers with relaxed amp, bright amp with relaxed speakers, etc], this is where it gets much trickier. Choosing a DAC then becomes more of a subjective pursuit.

DACs are not plug and play. Stick an U/OS DAC in with a bright sounding system and there is a strong possibility that it will sound like crap, regardless of how good it is. Same goes for an NOS DAC in a relaxed system.

There are exceptions to these very general statements. If you are a detail freak, don't even consider an NOS, you won't like it. If you can't stand anything forward or bright sounding, don't even consider an U/OS DAC.

That said, the thought that an NOS DAC can't do complex music is wrong. What I suspect happened (TCG and others) was you tried a 'relaxed' sounding DAC in a relaxed system and it didn't work. To give an audio analogy, its like using a cheap 20 gauge power cord to power a Krell Evolution 900 monoblock. That power cord, while it will power up the amp, will make it sound closed, constrained and undynamic (forgetting about the obvious current requirements of the amp). It is a mismatch, pure and simple. TCG, here is another one that you can appreciate...its like a cartridge and arm mismatch on a turntable. If your paired arm/cart resonant frequency isn't between that magic 8-12Hz, there is a strong possibility that combination isn't going to sound good.

Where things get even dicier is when you don't have a solid frame of reference as to what your system 'sound' is [relaxed or forward]. There are tons of people out there that don't have access to hear comparative systems so they can benchmark their own. For you guys, its a crap shoot. About the cheapest thing you could do is try a current model [cheap] DVD player in your system. Most all of the new ones are U/OS. Granted, it may not do all of the audiophile things you may enjoy but it should give you an idea of what U/OS sounds like in your system. If it sounds too forward and bright, you may well be a candidate for NOS. If it sounds close to 'natural', then there is a good possibility that your system sound is slightly on the relaxed side of the spectrum and U/OS is for you. Then again, feel free to toss out that entire concept if you are a detail freak or relaxed freak.

So what I'm getting at with this post is, NOS and U/OS will not work well in all systems. DACs are not plug and play. Think of picking DACs like you do matching cartridges to tonearms. You have to find something that

be a good match to your system. Take into account your system 'sound' then your listening preferences and then make the choice for which DAC scheme 'should' work best in your system. And for goodness sake, don't just buy something because its all the rage.

...and please, don't make carte blanche statements about a given DAC scheme. Its all about proper system synergy.

Mariusz · « **Reply #19 on:** 9 Jan 2009, 07:10 pm »

Nicely said. Great post Brain.