Canuck Audio Mart

Found one....

http://www.head-fi.org/forums/f7/nos-da ... bs-438220/

Very interesting,still so many questions

tubeornotube

Ok,I now have read many of the posts on the link I posted and I am under the impression that those who listen through headphones are either

a)playing too loudly and have hence damaged their hearing to such a point that they can't tell the difference between the old DAC chip sets and the late upsampling DAC's..lost all their high frequency perception..

b)cannot hear the difference through headphones anyways because of the limitations of such listening...no imaging..the music is in your head,not about you and outside your head as it is in reality..therefore the 'extra information' or 'detail' cannot be heard anyway..

c)as one poster on headfi said(and I interpret as),listeners younger than 34 yrs are becoming accustomed to the sound of lower resolution music downloading sytems..
hence have never truly experienced the real sound of instruments and the human voice..in a good acoustic space,not inside the headphones,earbuds or whatever

There was a reference to 'too much information' and that in a live performance one does not hear such nuances and detail..

WOW,all I can say after reading that is high-fi as we older persons know it is definitely taking major strides backwards...I would love for any of these younger listeners to experience a truly high-end system...and to go and actually listen to a live performance of any type of music that utilizes real instruments and little to no amplification...then come to me and tell me about their experience and what they heard...

I should like to send these people a box of Q-tips to clean that wax and other stuff out of their ears..

tubeornotube

I agree that this is a big problem. I am older but listen to a lot of current music, much of it in the indie category, but not really indie as it used to be, now it's big-buck indie. Tend to be younger people, early 30s and less. Great music. Absolutely horrible production quality values, yet I can tell they're trying. They just don't know any better. Very discouraging. Especially in Canadian music, which is very good now IMO. It is hard to find anything current (Canadian "indie" I mean) that doesn't sound like the master was a 128kbps MP3, has all the sonic telltales of that. I'm not sure that's not what they are in fact.

And yet I can go to musicians who are maybe just a bit older, and their recordings are excellent. We're not talking fancy production here. We're talking people who know how it should sound and approve the masters, vs people who really have no idea how it should sound and are going by how they're used to things sounding on their iPods.


As to NOS DACs, they are very pleasant for accoustic and other small combo/band recordings (electric or accoustic). They do get congested with more complicated ones, finer details can sometimes get obscured. For the type of music/recordings I listen to, NOS DACs can sometimes be a godsend in that I *want* them to obscure the nasty details. Generalisations. All NOS DACs are hardly equal, a good one is still quite expensive, and they are trivial to make cheap and cheap-sounding like most of them are (why they were ditched in the first place). IOW don't think you're going to save $$ by going NOS for a certain quality of sound, the DAC chip(s) itself is an insignificant part of the cost equation to good sound in a DAC.

I think I would worry more about compatibility problems with outboard dacs.

Jitter, clocking and timing differences.

In other words there a lot more involved than just upsampling and oversampling, straight 44, or 192,one bit and multi bit.

Now throw pre and post echoe into the mix(meridian 808.2 and Ayre mp-appodozing filters) and sampling is just the tip of the ice berg.

Check out the Uber clock from Vaccum state audio.

Some pretty good arguments about what really matters in a DAC.

cfraser wrote:

"As to NOS DACs, they are very pleasant for accoustic and other small combo/band recordings (electric or accoustic). They do get congested with more complicated ones, finer details can sometimes get obscured."

Would the above be true in general for all NOS DACs? Or can a good design work around the "congestion" with more complicated music?

With a non oversampling dac you need a form of filtering to remove the unwanted spuria/artefact of conversion to replace the oversampling brick wall filtering.

The analogue filters (some are low order) used in non os dac can often cause roll off in high frequency and some phase problems but still it may or may not be audible and desirable. It can have effect the amplifier/speaker combo also. Just imagine an amplifier presented with harsh high frequency harmonics trying to drive a speaker with a very low impedance in high frequency like an electrostatic.

You also need to consider the time domain ringing of your selected type of sampling and filter. Some have pre ringing other post ringing and it is believed to have an effect on the sound reproduction we hear. There was a good paper published on a old stereophile regarding this issue but I can't find it online.

I've heard non os, os (4-8 times) and upsampling dac and I can't really point which is better since there is more important concern that directly effect the sound. I've heard a good and a bad sounding tda1543 non os dac in different implementation.

I wouldn't buy a dac because it's a non os, os or upsampler dac.

Didn't see an answer to upsampling versus oversampling. The two terms usually don't mean anything different in other spaces, but in the audio world they've taken on two distinct meanings.

Upsampling is used when referring to changing one sample rate to another, like 44.1kHz to 96kHz, and remaining in the digital domain. The two sample rates may not be an integer multiple of the other, which means the upsampling process has to decide exactly how to spread out the samples. But 48kHz to 96kHz is an integer multiple, so you could just zero-stuff an extra sample in between.

Oversampling is used when referring to the DAC chip process of oversampling for the purpose of digital to analog conversion. This is always going to be an integer multiple, and it's done for more accurate and precise reproduction.

A higher sample rate, achieved through either upsampling or oversampling, allows you to use a much steeper filter with less effect on the audible range we actually care about. Even if you use a non-oversampling DAC chip, if you upsample the signal before feeding it into the DAC, you get these same benefits. So you can see how upsampling and oversampling are very close to each other, if not often the same thing.

There are downsides to using too high a sample rate though (ignoring any discussion of interpolation or non-integer multiplication), as DAC chips usually have slightly worse performance at a higher sample rate. You can see this on their published datasheets. Downstream components will also have more frequencies to deal with, but that usually shouldn't be a problem.

Nothing is true for "all" DACs. Most commonly seen NOS DACs at the lower end (such as TDA1543) will barely get you 14 usable bits of resolution. Most actually less in practice, though they'll never mention that. So that can't be easily overcome as far as detail recovery. I notice the reduced bass articulation the most as that's an area I like to hear. Also a reduction in bass dynamics and a rolled-off high end. I think all NOS DACs I've heard exhibit this to some extent. Which doesn't mean they sound bad, au contraire. I would like to have a really good NOS DAC for many recordings, and a non-NOS for others.

DAC output circuitry (buffer) and filtering can make all the diff in the world. (Let's take a good power supply and layout as a given/must-have.) I am not sure why there is so much emphasis put on these super-clocks these days, a bit of marketing hype and product differentiation I guess as is usual in this biz. The clocking is rarely the biggest problem I have with the sound of a particular DAC (<$50 should fix that in most cases), much much bigger fish to fry but audiophiles like to obsess over the last little detail they can easily understand, while the big/real problems that they can't easily grasp are politely ignored. Such as a manufacturer's whole methodology for doing something, it often creates problems they are proud to tell you they've "solved" with greater complexity and price. Self-created problems. Kinda like government.

I used to own a Lite Audio AH NOS DAC which ran 8 paralleled 1543's. I found it a very capable performing DAC, especially for the very low price. It was very soft sounding, though mine had a COEM mod to it (caps in place of op amps) and had no serious issues discerning complex music.

On the recording side of things you want higher bit depths to account for post recording truncation issues which could lose you bits but, at the playback end of things, 14 bits (84 dB SNR) is way more bit depth than anyone would ever need if playing back any common audio signal that we'd encounter. In practice, 12 bits (70 dB SNR) is likely enough.

Well, I had a DAC here that used 60 of 1543s paralleled. This number of DACs gave you ~14.5 real bits of resolution instead of the maybe 12 of one chip. I could hear huge differences in the highs and lows compared to what I'm used to, and yes I'm picky about the output stage. This was a great sounding DAC, I really liked it a lot (hope the owner gets tired of it and offers it to me first* ), but there are things I know are missing because I've heard them on much more resolving and dynamic DACs including my regular one. This DAC would be good for jazz and classical, and medium pop, which is just what the owner listens to. I listen to crunchier music and crunchier recordings; it's the crunchier recordings I have this DAC in mind for. What it did to some of them IMO was amazing. I do listen to some "nice" stuff too LOL, and then I really don't hugely mind whether I have a NOS DAC or a super-resolving one.

* I would make a few mods that *I think* could resolve my quibbles, but they might destroy some of the character I liked. Can't exactly test that out on somebody else's DAC, though I had it here for months and the owner probably wouldn't have minded. I am just wary screwing with other people's gear...makes me uncomfortable.