NOS verses Oversampling ? Choosing a Dac

[NRG]

LOL. There's nothing "closed in" about the sound of the DAS-R1 (using the 1541s you describe), either!

With respect, Neal, I'm not really interested in what can be 'measured', simply because measurement apparatus is often not compatible with what's considered as natural (or 'accurate') when processed through the auditory complexities of the human ear (and the brain's interpretation of it).

Basically, things aren't that simple because we (as 'complicated' humans) don't always hear music in the way an oscilloscope measures sound, which makes one question how relevant some scientific measurements actually are in hi-fi applications.

With hi-fi systems, too, the sum of its constituent parts is always greater and of more relevance than the individual effect of each component. However, that aside, I stand by my comments earlier in reference to your "slightly rolled off/closed in" remarks regarding the 1541A:



That's what my ears and experience tell me, not an oscilloscope

Marco.

Good for you Marco, I'm glad the DAS-R1 is as good as you say, no doubt due to Sony knowing how to implement the 1541 correctly. However, measurement is important and while you may not place any merit in it I bet the Sony engineers who worked on the DAS-RA bloody well did.

You need measurement to give a base line you can't design without....well you could try but....

[Marco]

Neal,

I didn't say that measuring stuff wasn't important (of course it is); merely that some measurements may not be as conclusive as you might think...

The reason why measurements aren't of interest to me personally is because I don't design stuff, D.I.Y or otherwise. I just buy equipment and listen to music on it, hence why I will always trust my ears and (quite extensive listening experience in this area) before the readout on anyone's oscilloscope, no offence

Based on that, I maintain that the 1541A (when correctly implemented) is not in any way "rolled off" or "closed in"

Marco.

[Tom472]

Without wanting to flare up any arguments, I was under the impression that when you oversample a signal, you don't get any more or fewer samples - rather you get more "gaps" between the samples. The reasoning being that when you unsample the higher frequency signal, the unwanted sidebands are shifted further away from the audio range (and so easier to filter out).

What strikes me is how little difference it actually makes (there is a difference) but I've A/Bd and old CD player switching in and out the oversampling and the difference is quite subtle. Makes you wonder why the Philips engineers went to all that trouble when designing early CD players.

Anyhoo, back to the original question - I guess the answer is you'll have to try different DACs to really see which you prefer (cop out). The Beresford does come so highly recommended however that you probably can't go wrong as a starting point.

Cheers

Tom

[leo]

It gets confusing guys I tried to stay away from this thread for as long as I could because the only thing I can add takes it way off topic from the original post

I have not listened to a 7520 or the Valab mentioned in the first post.

From experience I don't like using older dacs in parallel like the Valab uses (I have my reasons) I've tried it before to satisfy curiousity in diy designs but didn't stick with it.
I've also heard that the Valab had a few quality issues with the capacitors it used, this may now have been sorted out in the later batches?

A few of the older dac chips can be used as NOS not just the TDA's because unlike newer stuff the digital filter is external rather than internal in the actual dac chip

Having the digital filter, I/V etc etc inside the actual dac chip makes designing cdp's and external dacs much cheaper, easier and far more compact.
Like most things cramming as much technology into a single device can have compromises.
This is not to say all of the all in one chips are shite because they are NOT, like everything else you have to find the best performing part to suit your needs

TDA1541 is still one of my favourite chips but it also has a lot of downsides

Circuitry needs to be much more complex, larger and expensive, it needs more powersupplies with different voltages including two which are -v.
The chip itself is no longer produced so does not comply to ROHS (it contains lead) so a lot of countries with these ROHS regulations can't use it anyway in their new products.

Upside is get it right and it sounds fantastic IMHO! but at a price
The downside mentioned above is an advantage to the tinkerer as we have more freedom to fine tune having all this circuitry external to the chip

The mistake some people make is that they buy say a cheap old cdp using the TDA1541 , take out the SAA7220 digital filter and expect perfect NOS, not surprising it does not sound that great because the output stage was originally designed for oversampling.
Theres quite a lot involved One of the diy dacs I use was designed to be used with NOS, nothing I've heard yet can produce piano sounds as realistic as this one!
Swapping op-amps and using fancy arsed caps is not going to help either a simple converted dac or cdp made to be used with OS, it requires re-design

So without trying to drone on anymore if you want something cheap, convenient and not needing any diy I don't think I could recommend a NOS design.
The 7520 has had nothing but praise on here from what I've seen so maybe its the safest bet.

I've still yet to hear a cheap commercial dac to outperform my diy dac, soon as I do I'll be sure to mention it.
Some of us are not into diy just to keep things cheap, its because we want the best sound possible TO US and this is not always possible with commercially made units

[StanleyB]

Without wanting to flare up any arguments, I was under the impression that when you oversample a signal, you don't get any more or fewer samples - rather you get more "gaps" between the samples. The reasoning being that when you unsample the higher frequency signal, the unwanted sidebands are shifted further away from the audio range (and so easier to filter out).

There is a lot of misunderstanding about oversampling. Some folks even confuse upsampling and oversampling.

What strikes me is how little difference it actually makes (there is a difference) but I've A/Bd and old CD player switching in and out the oversampling and the difference is quite subtle. Makes you wonder why the Philips engineers went to all that trouble when designing early CD players.

The best test record I have found to check out the effect is Marvin Gaye - What's Going On. Listen to the vinyl with a MC cartridge, and listen to the CD on a 14 bit NOS, 16 bit NOS, 8X OS, and 64X OS. The appearance and disappearance of certain instruments and sounds is the one thing that is so striking. Why it is, I have no idea.

[nb2]

I guess a lot of you already know that, but there is very useful information about sampling and oversampling on
http://www.lavryengineering.com
Have a look at the "White Papers" in the "Support" section.

[ReachtheSky]

Hi Don,

To me, it's the digital source that makes all the difference. Either DAC is made or broken on what computer you're using, the operating system, whether your files are compressed or not, how your computer is connected to the DAC and how good the interconnect is between the two. If you don't pay attention in all of these departments, you'll have a hard time telling the difference between DACs anyway.

Hi Rich, I’m very interested in you comments about the effect of digital sources. I recall you did comment on this matter in another thread, but I’d appreciate a sort of summation of your views on digital sources.

I am in the early stages of moving from CDP/DVD source to computer/HD based digital source and would be most grateful for your views based on your experiences.

Thanks Granville

[lovejoy]

Hi Granville,
I'd be more than happy to share my experiences. It's all still very much in the work in progress stage, which I shall elaborate on, but I think it will require a new thread...

[ReachtheSky]

Yes a new thread would be appropriate.

[becseattle]

Well I actually use the 2009 Valabs DAC, and I have compared it to many others, as documented on other fora. The whole Ebay shippping and Paypal was smooth, and the producer quite responsive to questions. It's an excellent NOS DAC, and I prefer it to the usual list of NOS candidates.

I have also been through umpteen other DACs, and while the limitations of NOS DACs are pretty clear, I like it better than the many upsamplers/oversamplers I have put into my system. On paper I see the appeal of a Benchmarks etc, but in practice I usually prefer the NOS sound.

I use DACS with a Macbook and a SB2 wirelessly, and the rest of the system is YBA Passion Integre and Audio Physic Virgos. I found that the addition of a linear power supply made a bigger difference with the SB than any particular DAC of a class. Head to head I still prefer my Naim CD5/Hicap, but I seem to use the SB most of the time.

Bruce