NOS DAC - Marketing BS? - Page 2

The desire to remove high frequency energy isn't only applicable to DACs and audio electronics. You will find pass filters on all sorts of electronics specifically to remove unwanted frequencies. Some of the filters you find on a DAC may not even be related to the DAC chip at all.

It's also desirable to minimize unwanted radiated energy. Even if what you plug your interconnects into can handle some noise, something else unrelated might pick up the noise and be affected. That's why U.S. citizens see references to FCC Part 15 Class B all over devices.

I think Dan has been a little defensive, but I cut him some slack on this. I have not heard his dac to know if I like it, but I did read his paper in detail and understand his engineering analysis (actually had some fun going through this, but as an old timer had to print it out to read it carefully). For reference, I did manage an honors EE from a top school, but went into software so you can discount my thoughts based on that.

The Audioholics link posted above does not really address this topic and seems pretty confused. I only raise this because there seems to be a big issue with people throwing around some technical terms and a few graphs and all of a sudden they are experts. The first graph represents A-D conversion, not D-A conversion. Many terms are used imprecisely which made me discount the whole thing after the forth paragraph. Take a look at the first graph. Two analog waves are displayed with different sampling rates. This is not up sampling at all (at least in the context of D-A conversion). Of course you get a better curve fit with more points. We do not have the benefit of going back and recording the source again at a higher sampling rate. This guy designs telecommunications equipment. The loop as cited is relevant in this domain, but very confused in the world of audio dac where we are not designing devices on both ends of the conversion. If you take the time, you will see that Dan's article is at a completely different level and frankly is understandable to non-engineers as well. The graphed data is very effective and starts with the digital mess that we have to convert.

I have not had the opportunity to listen to dacs with the various approaches (even if they are doing some filtering) to know what is best to my ear. I buy Dan's points completely, but do not know what sounds best. I am actively looking for a dac and am still undecided. I will need to find a way to listen to some of these to make a call myself. We just have to recognize that Dan is presenting some solid analysis here. If I remember correctly, he stated in another forum that the psychoacustical stuff opens a whole can of worms. To each their own on the personal opinion side. Some people like Vegemite as well (have to get that in there for my Ausie friends).

Thanks for pointing out the flaws in the article I linked to. I won't be using it again. I'm a science major, but I often find myself lost when engineering topics get deeper and deeper. It's nice to have people around here who actually know what they're doing, so they can tell me when I'm wrong

Berlioz, I am a EE and I have trouble following this stuff sometimes. Thank you for being so non-defensive. Let's just listen to some of these dacs and figure out what sounds best.

Hrm. I have a few questions that are related to NOS DAC in general.

1. If all NOS are inferior in design, how does RedWineAudio or similar NOS DACs have a high praise/reviews? is it our perception or our ears are hearing the technically inferior sounds and making it more comfortable as a good natural sound?

2. The latter description of using the filter was way beyond me. Maybe can you explain in layman's term? :-)

Regards

This is the best description of the difference that I have read-

"The difference between the non-oversampling DAC and the conventional DAC with the digital filter lies whether you attach importance on the accuracy in the time domain [NOS] or in the frequency domain [OS]. In other words, whether you choose the musical performance or the quality of a sound. This trade-off line defines the boundary of the current digital audio format ."

From here- kusunoki

NOS sounds like 'music is happening', while OS 'sounds like music' if you catch my drift.

Why is fast food a multi-billion dollar industry? Why do people buy massive SUVs when they could do with a car? You can't argue the merits of something being popular, or appealing to specific people to something being technically sound. I have not heard the red wine implementation of NOS but I have heard several solid diy builds - and the real kicker for me was to listen to something like Mahler at a decent volume, instead of feeling like you're on a mountain, it was confusing and gave me a headache - it seemed the more complex the passage the more I became anxious - this is something I never have happen with the Lavry DAC, or the Benchmark, the BelCanto III, McIntosh.

By my limited understanding of what dan says in a different post, is that all dacs are probably are doing a little upsampling even if it is just x2. Maybe they dont consider that upsampling since its way lower than what the currant dacs are doing. I have an isabellina and love the output. Even if it is inferior, i havent found an oversampling dac that I want more. Sometimes to much detail and resolution isnt a good thing. When you are hearing something live, do you hear every detail of the musical production. Probably not unless you are sitting in the middle of the stage like where the mics are positioned. Maybe the nos dac losses just enough of the detail to make a perfect recording in a perfectly quiet environment with perfect acoustics and perfect mic positioning seem a little more life like. The difference of having a normal amount of detail loss as if you are positioned in front of the presentation which will lose a normal amount of detail rather than being right in the middle of it getting more detail that is only achieved by perfect placement of mics.

I have an imperative to read and search out the reasoning & solutions behind the things I become invested in. Sometimes I wish this was not so, as it can become insanely exhausting. My goal is to find as transparent a reproduction system as possible, and understand as much of it's functionality as possible. My ideal is such that the DAC shouldn't color or shape the sound, that isn't it's job, it's job like the ADC is to simply reproduce as close to transparent as possible, the source. The speakers or the source media should add color to the sound that, if anything. The NOS is interesting as a retro design, but it's being sold as a simple solution being more accurate, when it's less.

Something that may be related to this subject is a phenomena that I've found when demoing a hifi setup at my work, to the public. It's often the case that when presented with a high quality recording replayed on our setup (Lavry DA11, HD600 or 650, pioneer cdp) they won't always react positively. For those that don't, I will reply the same recording, except encoded into a 192kbps Quicktime AAC (fed to the lavry through USB or toslink) and the same people that thought the native cd/pcm sound unpleasing (terms like harsh, overloaded with details, too much were used) found the 192kbps aac much nicer. Not terribly scientific, but they are results never the less that point to the group of people, men and women 14-36 might be growing accustomed to the softer sound of compressed music. I don't know for sure, I just thought it interesting to bring to the table here.

Yep, all DACs are going to be oversampling in some way or another...and yeah a DAC that doesn't filter at all is going to be like drinking unfiltered coffee -- full of crap.

I had a passive DAC, the Moodlab Concept with TDA1541 chip...no active output stage...it claimed to be NOS. The 1541 is a very old chip and while I don't know that much about it, it definitely is simpler than today's chips and probably does less to the sound...whether that's a good thing or not, I will decide when my Audiogd DAC8 comes.

My havana sure sounds better than anything I have heard in its price range...Dan plz send me a DA11 so I can compare...Ill go post alot in the music section so I can be headphone supremous too...

May I ask what tube are you pairing with your Havana? I am on the journey to pick up a Havana pretty soon..

So, if I get this correctly, Havana and red wine audio also perform some level of OS and filtering.. Just not telling us.. Is that about right?

We are assuming that they are doing some level of filtering buy upsampling. Only the designer would know for sure or someone like dan taking a look at the circuit.

Don't think Audio Note or Zanden DAC has any filtering, OS etc.