[moonboy403]

Dan Lavry from Lavry Engineering recently wrote a post in regards to Non-Oversampling DAC.

To sum it up, Dan said, "So the NOS DA is either a piece of very inferior gear, or it is an up sampling DA that some sales guy calls NOS while it is not."

I'm very interested in this topic regarding NOS DAC, any comment guys?

 

[KingStyles]

You have to believe your ears. Iwas just at a meet and listened to his premium model. It was good but i prefer my nos dac over it. I have also read a lot of people over at computer audiofile that perfer the sound of nos dacs. Some of it might be bs but that goes for oversampling dacs too. It just comes down to a well implemented nos dac or oversampling dac is going to sound great and ther are plenty of nos dacs and oversampling dacs that dont. Listen to both and see which set of qualities you perfer.

 

[anetode]

Considering that it is common practice for such manufacturers to wipe the model numbers from DAC chips, it is more akin to fraud than marketing.

 

[Xan7hos]

Considering that the most popular Nos DAC, the Valab came out at a very reasonable price (around a 1/10th of the DA11), it's easy to see why the Valab in general is so popular. I myself own a Valab (and plan to own a DA11 one day) and honestly I'm very content with the sound the Valab produces. Compared to a Carat Emerald, I felt that that the Valab offered nothing less than it. IMO I think the laws of diminishing returns greatly affects DACs

 

[Berlioz]

Quote:

Originally Posted by KingStyles /img/forum/go_quote.gif You have to believe your ears. Iwas just at a meet and listened to his premium model. It was good but i prefer my nos dac over it. I have also read a lot of people over at computer audiofile that perfer the sound of nos dacs. Some of it might be bs but that goes for oversampling dacs too. It just comes down to a well implemented nos dac or oversampling dac is going to sound great and ther are plenty of nos dacs and oversampling dacs that dont. Listen to both and see which set of qualities you perfer.

I don't think that you quite understood Dan's post. His point was not so much that NOS DAC's are inferior, but rather that there is no such thing as a non oversampling DAC anymore. All the DAC's that I know of subject the signal to some kind of oversampling, whether they claim to be NOS or not.

 

[mrarroyo]

Well it could be that Dan is correct and all those who are advertising NOS DAC's are "... very confused and un informed." Or it could be that Dan has a product to sell and he is saying so to sell it. I do not know but if we are going to speculate both scenarios are possible.

Frankly I believe like KingStyles and I say trust your ears. I have owned both types concurrently, and as a norm I prefer the sound of the NOS type. But we all hear differently.

 

[LingLing1337]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif Well it could be that Dan is correct and all those who are advertising NOS DAC's are "... very confused and un informed." Or it could be that Dan has a product to sell and he is saying so to sell it. I do not know but if we are going to speculate both scenarios are possible.

That's what I thought

. A lot of NOS DACs have sound to compete with the high-end stuff (FWIR and being an owner of one), this sounds like Dan is trying to protect his market!

 

[tosehee]

Well, either he's right and all NOS is just marketing BS, or all very well implemented NOS are indeed great and he's just protecting his business..

Either way, I don't think it matters as long as you trust your ears.

 

[ms142]

I think it's unfair to say he's protecting his business if he's not right (I own a NOS DAC, btw).

We know for sure, from an engineering perspective, that new DACs are better than NOS in SOME ways. That's what Lavry pointed out. Because of our limited understanding of psychoacoustics, however, nobody knows for sure whether NOS can be better than the new DACs in some Other ways (which is possible for example if there're minute artifacts in the over/upsampling process that haven't been quantified, or if there are common noises in the recording that are exposed by the lack of rolloff). The NOS DAC people could be pushing a good sounding product for bad technical reasons.

 

[thisbenjamin]

.

 

[Dan Lavry]

Quote:

Originally Posted by tosehee /img/forum/go_quote.gif Well, either he's right and all NOS is just marketing BS, or all very well implemented NOS are indeed great and he's just protecting his business.. Either way, I don't think it matters as long as you trust your ears.

I took the time to present iron clad technical information, as a service to the community. I do not appreciate your suggestion that I am trying to "protect my business".

My argument is technical, and the proper way to take issue with it calls for refuting what I said, which can not be done!!!

Dan Lavry

 

[Berlioz]

I feel sorry for Dan. I don't think anyone really understood or even read his post. If you can understand how a Digital to Analog Converter works, you'd understand how absurd the idea of a truly non oversampling DAC is.

He was merely trying to explain that a NOS DAC that contained an analog filter would be an inferior piece of equipment, and this is likely the case. Some NOS DAC's ignore the filter entirely, leaving it to the listeners ears to filter the music. Dan made a very technical and concise explanation, and I believe that people should at least read through his statement and come up with a technical refutation as to why NOS DAC's are better than oversampling ones, before saying that he's just trying to protect his business.

Also, a lot of Digital to Analog Converters that are marketed as being non oversampling are not actually non oversampling. Chances are, more than a few people on these forums who think they have a NOS DAC don't actually have one. Again, this is because many consumers don't understand what their DAC is actually doing with the digital signal, and just believe what the seller is telling them.

But don't believe what I'm saying either, just look it up for yourself. This is a decent place to start.
Upsampling vs. Oversampling for Digital Audio — Reviews and News from Audioholics

 

[thisbenjamin]

.

 

[KingStyles]

I appreciate the time and energy that dan has made to headfi and for his time and presentation at our meet a couple of weeks ago. I found his presentation a valuable learning experience along with his articles and posts that he has made. As having 2 years in electronic engineering myself, I can fully appreciate all the time he has put into designing his dacs. I could only comment on the sound of his dac with the darkvoice, which simply put, wont bring out all the goodness that his dac had to offer. I was using my d7000's at the time and could only compare to what I know my isabellina sounds like with them. With that being said, i am sure that if the right cd player and amp were connected through his 2002, I would think that it would scale up and surpass my dac and others. That doesnt mean that I wouldnt prefer the sound of my nos dac still. I must say though, I have about 5000 in source/transport right now and Im using a offramp to allow me to upsample and reclock going into my nos dac. So in my case, I kinda do have a upsampling nos dac but the isabellina by itself sounds good with out the upsampling. I dont have the schematics or know what chips are in it to base an opinion to say whither dan is correct or not on the posted statement.

 

[Dan Lavry]

Quote:

Originally Posted by Berlioz /img/forum/go_quote.gif I Some NOS DAC's ignore the filter entirely, leaving it to the listeners ears to filter the music....

Good that you mentioned it.

It is true that the ear can not hear the image energy. But ALL the makers of DA IC's including devices INCLUDING the old NOS days and up to now want you to use anti imaging filers. One can "take a tour" of the data sheets of DA IC's from AKM, TI, Analog Devices and the other makers, and ALL the application data shows anti imaging filters.

So if we do not hear it, why do we need it? First what is the image energy?

When you look at the low frequency signal right out of a DA IC, say 1KHz sine wave, it looks very similar to what it is supposed to be - a sine wave with some small steps. But look at a 10KHz sine wave, or better yet higher audio frequency such as a 20KHz, and the signal does not look anywhere near the sine wave shape. If you filter it above 20KHz it will look like a desired sine wave but what happens if you leave the filter out? The image energy got its name because the audio energy appears as a near carbon copy (image) around the sample rate, twice the sample rate three times the sample rate and so on. That energy is still high even at the MHz range.

The difference between the direct DA out and the desired signal is all high frequency energy, above audio. If the DA could drive the ear directly, all will be fine. But the DA does not make sound directly. It does not vibrate the air.

One needs to send the DA signal through additional electronic devices. The DA does not have the power to drive a speaker or a headphone. The DA may be driving a power amp followed by a speaker, or a headphone amp followed by a headphone, or a mixer or what not...

So what is the reason we need to remove the high frequency energy? You do not want to burden the electronics DRIVEN BY THE DA with unwanted high frequency that does not belong there.

An audio amp, a power amp, a headphone device and so on are designed to operate well when receiving audio signals. They are not capable of doing a good job of it while being disturbed by signals they are not supposed to process.

I can not think clearly while being hit on the head. One can not enjoy music while being yelled at loudly. The electronics can not process the audio well while disturbed by significant unwanted energy.

A good audio amp, driver, headphone... is not designed to operate under such conditions. It is designed to do audio when there is NO such energy, and that alone is a tough enough task. When there is a lot of high frequency (way over the audio range) riding on the audio signal, the electronics makes distortions in the audible range. There are many mechanisms at play (intermod, slew rate issues and more), but that is too technical for now.

The amplitude of the ultrasonic unwanted energy is pretty low for low audio sound, but at near 20KHz, with NOS, the high frequency amplitude is around the same as the signal itself! That corresponds with what I said earlier - move the filter cutoff to a lower frequency, kill all the highs, and convince some innocent folks that it sounds great.

So we can now put the argument "no need to filter, the ear can not hear it" to rest.

Regards
Dan Lavry