NOS DAC - Marketing BS? - Page 4

Dan, thank you for your detailed explanations and bringing it down to layman's words. I have no reason to doubt you and the whole pro-audio industry that by science the OS way is more accurate/superior.

I just don't understand why so many people (here on head-fi, other hifi forums, and even reviewers) find the so called NOS dacs to be more "musical", "vinyl like" and "less fatiguing". Its hard to call it placebo since there are a lot of different people who think this way of NOS dacs. Then can it be just euphony? Is it possible for people to just prefer the less than perfect sound of NOS? If that's the case, then I wouldn't mind to sacrifice a bit on the highs to get an overall sound that is more "musical", "vinyl like" and "less fatiguing", since most of the music occurs at well under 20kHz.

You are in fact asking me to get off the technical and talk about non technical stuff. I rarely do it, but I will make an exception.

Most often, when folks want to believe something, and they have nothing else to hang on, they try to claim that many others or that the majority share their view. Upon careful examination, most often such claims do not hold.

There are also a lot more people that do NOT like or use NOS DACs. In fact, I am not aware of any serious professional studio that uses NOS. I am a "major force" in the pro audio industry (music production), and I was not even aware of the fact that NOS is still around until I came to this forum! To my knowledge, this NOS is rather "localized small cult" in audio.

There are no IC makers that support NOS for audio for many years. Why do you think it is so? Can you answer my question?

I have no desire to get into argument about subjective information. I saw a whole nation, the USA get off track and back up the wrong guy and the wrong war for 8 years. I saw big marketing and advertising money used to wrongly stir a whole audio industry to go for 192KHz sample rate. Why be surprised at a small group that believes something is better when it is not? You can always find a few people that will like something, and others that will dislike the same thing. Folks talk each other into all sorts of things.

I do not argue about tastes, one can prefer the sound of finger nails on a black board, or the sound of digital clipping, and as long as it is a personal taste, there is no point to argue it. I am not surprised to see some small groups here and there that hang on to various false notions.

I prefer to talk about facts, thus stick to the objective. I talk about technical concepts. You may have noticed that I do not use posting to promote my gear, or to out down other people or companies. I stay technical, because it enables me to be objective and correct.

For me, good audio is about the ability to bring a performance into your listening environment with as little distortions and unwanted alterations. I pointed out that NOS is inferior in that regards, it ruins the response, it outputs unwanted high frequency energy, it alters the phase... A real good experienced ear, and/or a "guy with a scope" will realize what I say is correct. What else do you need to know? The acoustic performance when played by NOS is altered significantly. It lacks much of the highs, it pounds unwanted high frequency energy into whatever it drives, it has very high amount of phase non linearity… It can not sound right, if you want to hear music as it was in the original performance. When you listen to a real clarinet or violin, do you wish it did not put out the highs? Do you wish the phase to be re arranged before it gets to your ears?

And those old DA's IC's used by the NOS are from the days where distortions and noise were very high. There was no real 16 bit in 1990! It is not only about the loss of the highs

Of course I stand by my professional knowhow, which is based on technical reality and "mother physics", and it is no coincidence that the gear I design has so much presence in the so many of most respected recording and mastering facilities in the world. But when I some hear people come up with all sorts of ridicules observations, I do not want to offend them. Personally, I often wonder how many of the comments I am amazed by are by people that do not calibrate their ears with enough exposure to real quality acoustic performances. But at the end of the day, folks are free to like what they want.

I love music (I am a musician) and I love electronics design (I am a designer) and I am very dedicated to better audio, and my contributions are for those that share my passion for better audio.

Regards
Dan Lavry
Lavry Engineering

Thanks for comment and information Dan!

I know my perceptions are uncommon and I'll be the first to agree they might be a little crazy, but when the day is done and through, it really comes down to what you perceive as better to you... music is art, and art is and has always been in the eye of the beholder...

I can see where you might think that I've been misinformed by someone, somewhere, somehow, , but in all truth these all my opinions through years of letting my ears decide for me... "commonsense" or "street-smarts" I wouldn't call them though. I seriously doubt most common people share my view of music or my musical interests. When I wake up in the morning I'll pop in one of my thousands of ambient albums depicting smooth rolling tones and slow melodies that are more reminiscent of ripples in water than a full orchestra composition... I search for warmth, resonance... and stray away from high detail. Heresy, you all must be thinking!

Thank you though for correcting me on the differences of Interpolation and the idea that up/over sampling is merely taking in more decimal places to allow one to come closer or more accurately connect the dots to their original form. As I mentioned at the beginning of my post, I'm definitely not an expert on all of this, but I'm always willing to learn!

Would it be fair to say that the closer one comes to perfection, the tighter the dots and the less room for the connection to be made, the less freedom the tone has; to say it is more confined to its path and thus more accurate?

Would it also be fair to say that some of us aren't necessarily looking for increased accuracy/detail, but instead prefer the music to play more effortlessly without added boundaries of detail, that is less constrained and in-between the lines? If you were to hear the same band play the same songs in two completely different venues, with different room acoustics, you would have two different conceptions of that same song. You might actually prefer one over the other... I'm not saying that a live recording is anywhere near the same thing as a studio one; one only needs to ask a musician if they enjoy being in a recording studio 12 hours a day for two weeks straight to find out which one they prefer participating in.

I really don't want to get too philosophical in this post because the last thing I want to do is to preach; saying my beliefs should be everyone's. I don’t think they should! If we all agreed on what we thought sounds best, then wouldn’t we all be just one big swarm of drones; not to mention what monopolies in audio gear would be created. If you were wondering, I will never ever call myself an audiophile, in any sense of the word, but rather I'm lover of music as art in motion and like all other movements, one that is affected by its surroundings. Hearing is believing; and believing is individualistic.

I will say that I do believe, that there is a place for NOS DACs... I don't disagree that marketers feed off of trends and if people who buy their products believe that their NOS DACs are more accurate and precise in their sampling than their counterparts than that's nobodies fault but their own. I don't believe that it is right to say that one person's sense of hearing is BS and treat them as such; in my very humble opinion that is the worst marketing of all.

hi again,

Leonardo was a great artist. So say we send the Mona Lisa to 3 guys. Say the first guy will see it with some extra orange tint, the second will see it with some smearing and less detail, and the third one will have 3 inches missing of the top. Will you call it art? Is that respectful of the art? I call it poor and not desirable reproduction.

You said music is an art, and I agree. But NOS is about poor reproduction of the art. A few folks here decided that they like the "picture to have less detail" and rather have the "top missing all together", and while at it "add some orange tint". If that is what you like, that is very fine with me. I would put it in the category of subjective personal likes, but I would not call it art.

Audio reproduction is about NOT ruining the sound. Music is an art, but I do not see how you can include a decision to have less detail, less high frequency, phase issues, distortions and noise under the umbrela of art.

You can find more of my stand on the issue here at head-fi (Lavry Engineering forum) a post called "about my design philosophy".

http://www.head-fi.org/forums/f158/a...osophy-432442/

Regards
Dan Lavry

There are many more believers in NOS at diyaudio (probably more than here BTW). I would not count myself among them and agree that it is probably the rolled off highs that account for the claims of greater musicality or more analog-like sound. And I also agree that passing thru very high freq. noise is not a good thing.

You may want to comment on that as reading your posts sounds somewhat conflicting when you state:
This might lead someone to wonder if it lacks much of the highs (i.e., rolled off response), how can it pound unwanted HF energy into whatever it drives?

1980's Philips chips seem to be the vast target of NOS DACs: TDA1543 and 1545s, and the venerable TDA1541A 16-bit chip are prevalent in NOS designs.

I will say it again:
When you look at the output of a NOS DA before the filter (or with no filter), you see that "stair case" type of a signal. That is the NRZ signal (not returned to zero). Each sample value is "held" until the next sample time. Those "steps" are in fact easier to see at higher audio frequencies (they are bigger).

For example, take a sampled 10KHz or better yet 20KHz, and you see very high difference between the smooth original wave, and the "stepped" sampled wave. The difference between the original wave and the sampled wave is found by subtracting one from the other. You can look at the paper I pointed earlier about sampling, oversampling imaging and aliasing.

When you examine (analyze) that energy difference, you find out 2 facts:

A.
Most of the difference in the energy is what we call image energy. It is in fact very predictable. It looks like a mirror picture around the sample rate (such as 44.1KHz), then it is also around 2fs (88.2KHz), and around 3fs and so on. In other words, a 1KHz sampled NRZ wave contains 1KHz tone, but it ALSO contains 44.1KHz +1Khz=45.1Khz and 44.1-1=43.1KHz. It also contains 88.2+1 and 88.2-1 and so on. What is worse is a signal that is 20KHz. The first image you see is at 44.1KHz-20KH= 24.1KHz. That is very close to audio and that image amplitude is the nearly the same as the 20KHz tone. How high does the image frequency go? Very high frequencies, but not “forever”. The image amplitude follows the sinc function (sin(X)/X curve), but you still have plenty of energy in the MHZ!

B.
The second fact is that the audio itself also follows the same sin(X)/X curve. The other portion of the difference energy "sucks away" amplitude form the audio range. At 1KHz, that curve does not cause problems (the loss is tiny), but by the time you get to 20KHz you are losing around 1.5dB with a NOS.

This is the time to quantify things. A 1.5dB loss in the audio range is a lot of sonic alteration. If the same same sinc curve may cause say around 6dB loss at around 44.1KHz that is still a lot of high frequency energy. For a 10V audio, you end up with 5V of high frequency around 44.1Khz, right along with the audio. You really want no audio loss and no high frequency energy (such as .1dB audio loss and -100dB of image attenuation), and with NOS you are far from such a goal. You end up with 1.5dB audio loss and the image is only only a few dB below the audio amplitude.

(Note: When you up sample, you are "stretching" that sinc curve in the horizontal direction (frequency), which lowers the high frequency attenuation. Up-sampling also moves the images to higher frequencies away from the audio range, and with a bigger "gap" between audio and image frequencies the analog filter is much less of a problem. Up-sampling help solve BOTH issues).

All that happens BEFORE you do any filtering. So with the NOS you have 2 things that happen at the same time - loss of audible high frequency amplitude AND the addition of a lot of high frequency energy. That is not a conflict, it is an iron clad fact.

A DA is not a filter. If it were a filter, you could expect that loss of audio high frequencies will also mean loss of other high frequency. But a DA is not a filter, and the process introduces high image energy while causing loss of high frequency audio energy. Don't view a DAC as a filter and it will not confuse you.

Now, you take a NOS, and if you leave the post analog filter out completely, you still have all the high frequency energy. If on the other hand, you want to remove the high frequency, you need to add an analog filter to remove that energy. Remember the above mentioned 44.1-20= 24.1KHz image? You want to remove it, so ideally we need a filter that passes 20KHz without any attenuation, and rejects 24.1KHz completely.

If you could have such a filter, you still end up with the loss of highs that comes out of the NOS before the filter. But the fact is, you can not have a practical analog filter that will yield say .1dB to 20Kz, and say -100dB at 24.1KHz. (you can do so with up-sampling but not with NOS). In fact you can not even have a real filter that will add 3dB loss at 20KHz (to the already existing loss) and yield say 60dB image removal at 24.1KHz. You end up with a pretty poor compromise.

So there is no conflict here. The signal out of a NOS has a BUILT IN loss of high frequency audio AND a bunch of high frequency energy all at the same time.

I hope it is clearer. I really can not continue to put so much time into the thread...

Regards
Dan Lavry
Lavry Engineering

Let me say I am by no means a technical type and have no desire to fully understand the technical merits of NOS vs OS, (not that there's anything wrong with that) audio for me is a means of pleasure, I don't make a living at it Like Dan does.

To start with digital is a flawed medium (Perfect Sound Forever?), whether you like NOS or OS is your choice and what fits into your system. In my system and IMO there is no mistaking the quality of sound from a properly set up analog source such as a turntable, then go back to digital and for me while it can still be enjoyable it just doesn't compare. For me the discussion of OS vs NOS is analagous to what Dan said, do you want back pain or neck pain.

For now I have chosen back pain and live with a NOS dac, I'm not married to NOS, I may hear an OS dac and flip over it. Many of us move from one piece of equipment to another piece over time, SET tube amps, solid state amps etc., there's more than one way to skin a cat and that's what makes audio fun, so don't get so caught up in technical talk and just enjoy your system, be it OS or NOS whichever sounds best to you.

Look at the old TDA1543 data sheet:
http://www.docethifi.com/TDA1543_.PDF
Under features, the device was already offering X4 oversampling.

Look at the TDA1545 data sheet: TDA1545 Datasheet pdf - Stereo continuous calibration DAC - Philips
Under features, this one "permits X2, X4 or X8 oversampling.

Look at the TDA1541 data sheet: http://www.datasheetcatalog.org/data...s/TDA1541A.pdf
The device supports X4 or X8 oversampling.

Phillips, the maker of those IC's was already into oversampling by up to X8, and that was way back then. In fact Phillips was one of the driving forces behind oversampling and up-sampling early on. Why would anyone choose to think that the IC maker would bother to offer IC's that can operate with up-sampling capability (they called it oversampling) up-front as a feature? They did so because of the advantages in up sampling that I mentioned.

The promoter of NOS chose to forgo the possible advantages offered by up-sampling. Some even removed the filter all together. I do not care to speculate here for the reasons behind that. I do not want to offend anyone.

One way or another, those very old IC's offered far lower performance than today’s DA's IC's. Yes I know. Some folks here and in the DIY group will insist that their own ear is the standard of quality sound, and that is really fine with me. I have a friend that loves to drive his Model T and it does not bother me at all.

I wish all to enjoy whatever they choose to. But I am for true quality, which is in my book reproduction of the real sound - it is called transparency. I have no desire to alter the sonics of Yo Yo ma's Stradivarius cello. I have no desire to alter the sound of a great Bosendorfer piano (such as my wife and I own and play). I do not want it warmer or colder, or crispier or fuller. I do not wish to knock the top harmonics and have phase related issues for vocal, trumpet or anything else. I want to leave the sound as it came out of the instruments and vocals at the original performance. There are very many people worldwide that share my passion for transparent sound (listening to the performance as close as possible to the original acoustic music performance). I do my designs for those that like transparent sound, and for myself.

Oversampling and up-sampling are major tools for reaching transparent sound.

Regards to all (both OS and NOS users)
Dan Lavry
Lavry Engineering

tubes, while I understand were you're coming from that isn't the point of this thread. this thread was created to address the questions of the forum members, in regards to the hype-pole surrounding NOS dacs and the accuracy of the claims of their proponents. Dan and others have done a superb job dissecting the technical aspects of this situation, and while the only defense brought up by the proponents of NOS dacs are "well, they sound good - to me" they continue to explain in as many ways as possible that these are antiqued designs that have no use in this day and age. I understand that you might enjoy the hardware you have, but your opinions on what you like aren't the point of this thread - and decrying your lack of desire to understand them is frankly doing a disservice to the time and effort applied to people with frankly far better things to do with their day.

Ok, I have to derail for a moment - that's incredible, you have what is arguably one of the worlds foremost concert pianos in your home?! Is that an 88, 92 or 97 key? What model / vintage is it? I know it's a backward way to come into knowing of the manufacturer, but Tori Amos has for years toured with Bösendorfer and after attending several of her performances were she would simply sing along with the piano, I was enthralled. Another amazing instrument out of Vienna.

The piano came with my wife, and we have been together for a long time so one can conclude that we are all vintage. This one is an 88 key, I think it is around 9 foot long. As you know, they all sound slightly different, and this one is one of he most incredible sounding pianos. I love it! I grew up with Bechstein, which is also a great piano (the brand is better known in Europe), but this Bosendorfer sound is "something else". I heard that the sounding board was pre aged for 40 years. I am not sure that is so. But one way or the other, the sound if great!. One can not complain about the action, and it hold tune for very long time, but it really is all about the sound.

Regards
Dan lavry

"SWM seeking SWF with Bosendorfer piano. Please send picture of piano."

Yeah, thisbenjamin I understand where you're comin from also. "Doing a disservice" please you must be kidding and your condescending tone sounds like you have a deep seated hatred for NOS, you can get help for that you know.

I think the only things I hate are Nazi Germany, and anything that halts or limits the evolution and progression of mankind.

As technical as this discussion is and as many times as it's been addressed, the "value" of NOS isn't up for debate here, the hyperbole surrounding it is/was (I think it's pretty much a dead horse at this point as I haven't seen a single technically sound argument for the use of it vs. current technology.) The best I can reason is that in the realm of geek chic / retro hifi it appeals for the sake of simpler times - akin to vinyl or tape, and I understand the appeal, but we're talking about digital technologies here. They are not in stasis; as our understanding of the applications, and fundamentals of the sciences increase over time, so should our implementations. Be thankful this is one area were we're getting better, not worse.