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Heres some test results for the new ESI Juli@ card. (Page 3)
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Matt: Heres some test results for the new ESI Juli@ card.
marcello
Junior Member

Posts: 5
From: Utrecht, NL
Registration: Feb 2005
posted March 16, 2005 07:04 PMprofileeditreply w/quoteIP

Maxim,

I talk about 4$ opamps and 2$ capacitors, not 100$ esoteric stuff.
In this discussion I go from bad to good, not from good to top notch or excellent to outstanding. That is a totally different league, only for my paying customers.
Standard capacitors are "bad". especially multilayer ceramics, those are piezo-electronic, microphonic; they actually GENERATE electricity! and all those commercial electrolytics they suck too.
See:
http://members.aol.com/sbench102/caps1.html

Standard opamps are "bad". The fact that everybody screams OPA2604 or 2134 is ridiculous. Those are "bad" opamps. See the following link for somebody who has studied this subject a little beyond what most of us have done:
http://www.dself.dsl.pipex.com/ampins/webbop/opamp.htm

Don't think that I only see a magic black box when I look at a converter.
I know very well what's inside it. It is my job to know.
I design electronics, and have evaluated, tested and tried almost every dac-chip out there to come to the right choice for each project.

For this purpose we have designed a multi-functional D/A converter board with the best clocks, excellent discrete analog stages, the best power supplies, controlled impedance digital lines (no reflections-no jitter), a central low-capacitance socket and a multitude of small pcb's on which all dac chips were mounted. All kinds of jumpers were used to accomodate each of the dac chips, so that -for the first time- all chips could be evaluated in exactly the same optimized environment.
The differences were clearly audible, and most people shared the same preferences for certain converters. No surprise there.

Then the next step was substituting the discrete analog stages for opamps. 90% of the differences disappeared, although the I/V-converters and output-buffers were made with excellent parts, and with a proper layout as recommended by all chip manufacturers according to the best RF-practice.
Now, substituting NE5532 opamps for OPA2604, 2134, AD8022, AD8032, OP249, OP275, OP285, NJM2068, OPA2277, all agreed that the differences in sound quality was bigger than the differences between converters. The range between opamps was from sounding "unbearable" (JRC/NJM series, OPA2604, OPA2277) via "fair" (5532, 2134, 8022,) and "good" (OPA249, AD8032) to only a couple that were unanimously regarded as sounding excellent, amongst them THS4032 and some LMH-types.
Everybody -in different locations, at different times, without knowing from each other- told the same story, that they found the differences between opamps more important than the differences in dac chips.
That is why in my experience it is that in sound cards the greatist benefits are obtainable in optimizing analog circuitry like opamps, capacitors, and clock. And let's not forget power supply and ground.
Anybody who thinks that it is a good thing to first change AD and DA should do so, but is putting the horse behind the carriage.

Your change from OP275 to AD8620 is no improvement, on the contrary, OP275 may sound even slightly better. OPA2277 is not a good audio opamp, really weird sounding, but AD8066 is not either. It is only OK for high speed applications like I/V-converter, but has much too much dynamic LF-noise and far too high O/L-gain to be regarded as a serious audio opamp. Result is noise modulation on your audio signal that will mask low-level detail. The feedback loop is far too busy, and destroys all positive aspects of the opamp.
Try THS4032 and bypassing the power supply pins with proper caps, then tell me if you still don't hear differences.

Once a guy told me "This Crystal DAC is better than your AD dac chip". I said "no way pal, it's the implementation".
We made a bet. Build the best dac board he could, I build the best dac board I could, with any opamp or whatever behind it, and compare the results. The best dac gets awarded a bottle of scotch.
For a hifi-show we prepared each one exactly the same dvd/SACD player and let the anonymus people decide which of the two sounded best.
I won. With my AD1955 dac, THS4032 I/V and buffer. He used CS4397 and AD8620/AD8632.
Then we did only 1 thing: Next day we swapped opamps, AD8620/32 in mine and my THS combo in his player.
He won.

This whole subject is -at this moment- part of a project in which the maximum sound quility is wanted for a 192kHz 24bits A/D converter. With already in this early stage some interesting results. Not measured results. Actual concert recordings, symphony orchestras in real concert halls. Big differences in sound between opamps and capacitors, and two different A/D chips sounding very similar.

Anyway, Maxim, long story but hopefully worth a little bit for anyone who takes the trouble to read and wanting to improve his/her sound.

Cheers,
Marcel

Maxim Liadov
Coordinator

Posts: 250
From: Moscow, Russia
Registration: Oct 2001
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posted March 17, 2005 05:38 AMprofileeditreply w/quoteIP

marcello

Thank you for so detailed explanations. You did great test and show us that for top model of DACs one need to use top op amps. That's undoubtedly. But we still did not see that a bad DAC with top op amps sounds better than a top DAC with ordinary good op amps. And keep in mind, we talking about soundcards here. I believe that for different classes of soundcards there is the golden mean without bottleneck. Isn't it?

Gordon McGregor
Junior Member

Posts: 12
From: South CA, USA
Registration: Jan 2004
Web-page
posted March 17, 2005 07:54 PMprofileeditreply w/quoteIP

Marcel,
I respectfully disagree with some of your statements, as follows:
1. Maxim was talking about budget DACs (and codecs), used almost everywhere in soundcards. When some good DACs started to be used, we've got Lynx Two (CS4396), RME Digi 96/8 (AD1852) and now 1212M/1820M (CS4398) and 0404 (AK4395), those soundcards are known as good sounding ones. 1212M/1820M uses budget JRC2068 and still sounds good. No doubt with better op amps it would sound even better, but I disagree that the quality of DACs in soundcards for the final sound quality is not as important, as op amps quality.
1. OPA2134 is not "a bad" op amp, I would definitely agree that it is "a fair" op amp, it is used in several award winning devices with good results, such as Anthem AVM20 or Lexicon MC-12, for example. No doubts, it is not the best one. It is recommended by TI (Burr Brown) engineers for using in LPF stage after PCM1704, it it's datasheet. Following to their recommendation I used it there instead of JRC2068 and it sounds quite good.
2. OPA2604 is not "a bad" op amp as well, it creates distortions, but several people prefer such distorted sounding. I never liked it though.
3. NO WAY OP275 can sound better then AD8620. It creates only odd harmonics at the level of approximately 0.001%, and AD8620 creates both odd and even harmonics at the level of approximately 0.0008% (it means more audible odd ones are significantly lower). This replacement had been proved by many modders, such as:
http://www.lcaudio.com/index.php?page=5
quote:
Replaces i.e. NE5532, NJM2114, OP275, OPA2604, AD712.
http://www.soundodyssey.com/AudioParts/OpAmps.html
quote:
To name just a few- The Op Amp list of shame: NJM5532, NE5532, LM318,
OPA2134, NJM2114, NJM4558, NJM4560, OPA2132, AD827, OPA2604, LF353,
OP275, OP275, AD712
And even Douglas Self said about it:
http://www.dself.dsl.pipex.com/ampins/webbop/op275.htm
quote:
Expensive, and nothing special. Probably best avoided
He never said this about OPA2134, for example.
4. AD8066 (dual version of AD8065) IS A GOOD OP AMP! I tried it by myself, and here is an additional confirmation:
http://www.lcaudio.com/index.php?page=5
quote:
AD825's succesor, the new super chip: AD8065!
Take a look at DIY people's opinions about it and AD8610/8620 as well:
http://www.diyaudio.com/forums/showthread/t-21225.html
5. I never tried THS4032, it looks that it worth to be tested. I tried more or less similar (several times faster though) THS4062, it is good enough. But I can't agree that 4032 is a TOP-NOTCH op amp, please list Top High End devices, where it is used. I really doubt that you can find many of them, if any one uses those op amps.
6. The discrete I/V circuits are still the best, such as Boulder's 963 stage, Ayre's discrete output, etc.
7. I have replaced OPA2227, not OPA2277, those are different op amps!
8. There is no audible difference in Lynx (well, may there is a difference, but I can't hear it in DBT) after op amps swamp probably due to the fact of quite high 7th harmonic (-112dB level, haven't changed with op amps swap), which is created there due to some other devices, other then op amps, AFAIK. 7th harmonic is the most audible one, as we know, and it is the only one in Lynx Two above the threshold of audibility.
Regards

[Edited: Maxim Liadov, March 18, 2005 08:15 AM]

Maxim Liadov
Coordinator

Posts: 253
From: Moscow, Russia
Registration: Oct 2001
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posted March 18, 2005 08:16 AMprofileeditreply w/quoteIP

Gordon McGregor
Fixed.

marcello
Junior Member

Posts: 6
From: Utrecht, NL
Registration: Feb 2005
posted March 18, 2005 06:38 PMprofileeditreply w/quoteIP

Gordon, Thanks for your interesting post.

I was taking the AD's and BB's and Crystals as examples, but I could as well have mentioned the various AKM chips that differ very little between them, except in some odd specs. The fact theat I omitted AKM might have confused the arguments a little, so sorry 'bout that.

Don't fix yourself too much on either
1. what other modders say or find and
2. distortion figures.

There is a lot more to sound quality than distortion. Noise modulation for example. Robbing music from details and leaving you with the impression that you are missing all kinds of information but you don't know what exactly.
Noise modulation is different in every setting, coloring the sound differently in every occasion.

Other modders listen to nice sounding opamps while using LM7815/7915 crap or LM317/337 noise-and-distortion- generators in the power supply.
That is not doing any good to the opamp in question, and puts you on the wrong foot. You are not evaluating the opamp's sound quality there, only listening to the contributions of the regulators and the opamp's sensitivity to that. Look at PSRR in higher frequencies, and compare +V PSRR with -V PSRR. If they are different, you'll understand what will happen.

That is why I said, and say again, that it is of utmost importance to clean up the power supply. Before you do any serious evaluation of opamps.

In my opinion, but that is not necessarily yours, the differences in sound quality between really good opamps and OPA 2604 and 2134 is so big that I happily warrant the latter two the title of "bad" opamp.
I agree that they sometimes do sound "fair", but that is still not my definition of "good sound".
And in this world of high resolution audio and $4 top notch opamps it is a disgrace that commercial equipment is equipped with clearly inferior chips, and then labelled "top quality". It is clearly misleading the public.

Re. to the links in your post: Soundodyssey are telling a popular story with the intent to sell their own stuff. Be careful. Exaggeration is just around the corner. LC same story. They needed a successor for their sales-hit AD825 that went out of production. They need cash. Whatever they say, is believed. Don't fall into that trap. Use your own ears and imagination, and intelligence.

THS4062 vs 4032: 4062 is not in any way similar to (let alone better than) 4032 when we talk specs that matter to audio performance.
4062 is 180MHz vs 100MHz (4032); Slew Rate 400 vs 100V/us, but there the rally ends.
4032 is clearly better in the following areas:
Settling time to 0,01%: 80ns vs 140ns for 4062;
distorsion: -90dB vs -72 dB (that is 8 times better folks!)
Noise: 1,6nV/rtHz vs 14,5 (yes that's 9 times better);

Which is clearly enough to suspect that the THS4032 could well be top notch and the 4062 certainly is not.

Sorry, I read OPA2277, my mistake. Those are indeed very different. OPA2227 being horribly slow. Good for small input signals. Not for high resolution.

Again: you may not be hearing differences in the Lynx because of bad, polluted psu and gnd.
I doubt if you will hear 7th harmonic at -112dB. Calculate environment noise (50dB), max sound pressure level (+110dB) and -112db artifact. Inaudible. Your 7th harmonic would be -52 dB below environment, when you play at 0dbFS.
Human can discern discrete tones up to 20dB below the noise floor, not 52dB.


Maxim:
Sorry. Bad dacs are bad. They don't count. Decent dacs like AKM and all the rest may step into the ring for comparison, bad dacs may not. This is not about bad dacs. This is about sound quality between acceptable dacs.
The Yamaha I talked about has relatively cheap AKM codecs. Still the differences were certainly big.

Just finished 2 soundcards, M-audio 192 and my own Juli@. No change of AD/DA's (almost similar AKM's), but replaced clocks, opamps and capacitors. Results are that the sound quality is now a WHOLE lot improved, quite close to my high-end A/D (PCM4042; close, not there) and D/A converters for cd/sacd/dvd players. I am sure when I make a special linear power supply for the cards that the sound quality will be even closer the best converters I have made.

Small differences will remain, but most if not all masking and dynamic misbehaviour, that blocked my view into the recordings I have made, are already gone.

No sweat about typos, I read messages and opinions, not loose characters.
Cheers,
Marcel

Gordon McGregor
Junior Member

Posts: 14
From: South CA, USA
Registration: Jan 2004
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posted March 18, 2005 08:41 PMprofileeditreply w/quoteIP

Marcel,
Thanks for your response.
Again I disagree concerning opinions of different people, including modders and DIY members. They have no point to lie, their business or interests are based on their opinion. We all have our subjective hearing evaluations, why do I need to ignore their opinion and accept yours?
Distortions are very IMPORTANT if we know how to evaluate them (a spectrum). For example, here is a graph of audibility for distortions, created by Steve Albini: http://www.poonshead.com/harmonics2.gif Using it we can difine and explain MANY situations why we hear something or not.
Here is the whole article: http://www.poonshead.com/articles.html
Our hearing system is some kind of spectrum analyzer, it evaluates sounding using the specrtum envelope. The spectrum of harmonics is very important - for example Seebeck (and later Schouten) showed that complex periodic sounds with NO energy at the fundamental may still give a clear pitch sensation at the fundamental.
And yes, there are MANY other factors, relative to the sound quality - noise modulation, noise background, slew rate distiortions, TIM distortions, etc. etc. In our examples we are talking about:
1. Subjective listening evaluations - I provided opinion of many people vs yours.
2. Measurements - OK, I am ready to discuss other factors if you will provide the results of measurements for them in comparison between op amps or DACs.
It is easy to check anything in op amps sounding, using a battery power supply - in this case we eliminate any influence of the power supply.
In your previous post you state first that 2134 is a "bad op amp", and then you state that it is "a fair op amp". Where is the truth? If it is so bad, please explain to me these facts:
http://www.anthemav.com/NewSitev2.0/AnthemProduct/AVM20/AVM20.html - "Best of 2001", "Best of 2002" how could it be possible (AVM20 uses 2134 everywhere)? Find me anyone who thinks that AVM20 sounds "bad", please.
And then: http://www.smr-home-theatre.org/Lexicon/mc12/smr_image_05.html
Do you think that Lexicon engineers, known as very professional ones, would use OPA2134 in their flagship MC-12 AV processor with ~$10k price (so they can afford to use any op amps), if they are "so bad"?
Finally: http://focus.ti.com/lit/ds/symlink/pcm1704.pdf fig.5 (page 9) Do you think that Burr Brown engineers would recommend to use "a bad" op amp to use with their TOP multi-bit DAC?
I have more and more similar examples, and in addition I've tested and used OPA2134 by myself. It is "a fair op amp", not bad.
I can understand your meanings, if you are on the perfectionist's side of the world and anything which is not "the best", is "bad". But in this case I don't understand why your meanings are not working for DACs - we have exactly the same situation here, as with op amps.
Soundodyssey lie, LC - same story, then Modwright, Parts Connecxion, etc. etc ... This is not true, because I tested AD8066 by myself. I lie too? But I don't use AD8066 anywhere, I just tested it - what is the reason for ME to lie then?

Concerning THS4032 vs 4062:
1. Settling time is 90 vs 140 - I doubt that is is SO bad for the sound quality, taking in consideration, that OPA627, which I LOVE, has significantly higher settling time, and still sounds great.
2. Distortions - you have to pay more attention to the datasheets, man. The level of distortions for THS4062 is -72dB at 150 ohms loading (see fig 20 and fig 21), they just mentioned the worst case. Distortions for THS4032 are -72dB for 150 ohms loading - exactly the same!!! They just used another loading data in addition to the worst case, and stated -90dB at 1 k loading.
3. Input voltage noise - here is a serious difference, but if we are talking about an I/V stage, we need to use input current noise data, and it is 1.2 in THS4032 vs 1.6 in THS4062 - I doubt that anyone will hear such difference.
Though as I said before - THS4032 is an interesting op amp and it worth to be tested. Thanks for the info.
I never said that THS4062 is "a TOP NOTCH". And finally do we evaluate sounding of anything by datasheets, do we?

Concerning Lynx - NO WAY I can't hear the difference because of psu and gnd - the level of noises is -114dB as well as DR in the LOOP test, it means for DACs and analog path is is even lower, as we add here ADC processing.
In accordance with Albini's graph we can hear this level for 7th harmonic. Do you want to write an article and dismiss his results? Let's use your data then.
I used the headphones for DBT of the L22 soundcard, therefore the environmental noises were significantly lower. I switched off all "sounding" devices, and I live in low noise area. I doubt that is was 50dB.
The reason why I couldn't hear the difference was in the fact, that the spectrum of distortions hasn't changed with op amps swap. It sounds strange, but something else creates distortions in Lynx, and the level of distortions in op amps is significantly lower. This is what I know at the moment.

Your own Juli? Esi Juli with it's budget codek AK4358 (THD+N -94dB DR 112dB - DR for the DAC is worse then DR in the WHOLE Lynx L22 soundcard - in the LOOP measurements), and this is visible in the Juli's loop measurements: http://www.ixbt.com/multimedia/esi/julia/esi-juli@-2…bu-balanced.shtml - only -103.4dB DR, 10dB worse then in L22/Lynx Two?
And you are talking about "bad and fair" op amps here and "bad DACs, which don't count"? "WHOLE lot improved [with such DACs???] and "QUITE CLOSE to your HIGH END A/D"?
I am completely lost, man.
Cheers.

[Edited: Gordon McGregor, March 18, 2005 08:57 PM]

temporary
unregistered
posted March 18, 2005 11:28 PMeditreply w/quoteIP

Lots of arguments but not seen any evidences yet.

Can you give some RMAA graphics for modded juli@ compared to original that would show the differences on DACs or other stuff you're writing 'bout.

In my opinion, if I can hear some difference in sound, it has to show somehow in test results (like RMAAs graphics) too.

Gordon McGregor
Junior Member

Posts: 15
From: South CA, USA
Registration: Jan 2004
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posted March 19, 2005 01:09 AMprofileeditreply w/quoteIP

It doesn't worth to swap DACs in soundcards, temporary. This is why people tweak only analog part usually, power supplies, coupling caps, etc., but not DACs. Though in Lynx Two CS4396 can be replaced by CS43122, as they are pin-compatible, but it will give nothing for the sound quality, as specs are quite similar.
I agree that if we can hear something, it can be measured, but the question is - on RMAA graph you can't see TIM distortions or slew rate distortions or phase/group delay graphs.

temporary
unregistered
posted March 19, 2005 02:22 AMeditreply w/quoteIP

OK.

Then, would changing analog parts (or any/which other parts) make any difference when we're talking 'bout 'stereo crosstalk'?

Is it one propetry of the converters or is it more depending on op-amps?

marcello
Junior Member

Posts: 7
From: Utrecht, NL
Registration: Feb 2005
posted March 19, 2005 06:15 PMprofileeditreply w/quoteIP

Gordon, Thanks for reaction, lots to think about!

-Okay, I will pay more attention to the datasheets, man. Be in for some surprises. See below, where I will do some interpretation of specs.

- Don't feel attacked. You write as if you have to defend yourself against all kinds of words that I have put in your mouth. Lighten up, I did not.

- I never called you a liar. Not explicitly, not implicitly. Do not throw that at me. It's not fair.

- I never said you have to believe me. Just try and see for yourself. If you want to have an open mind, then you are condemned to investigate yourself. And interpret your findings. And be stimulated by others. Especially when they say things that differ from your own conclusions.

- I never said that you called the THS4062 top notch. I just repeated a word YOU started to use somewhere, as if I had used it before, which I had not.

-Printed the Albini article. Thanks, interesting. will read it.

-Most of the Modders and DIYers have VERY limited experience and knowledge for getting the best out of a part. Hobbyists. Most of them run after firmly stated opinions and get stuck with bad designs and sub-optimal sound. Typical behaviour. Humans need signals, directions, guidance.
But as long as they wish to listen to fixed voltage regulators for example I certainly cannot take those opinions seriously. But I do not say that they are lying. Just that they ain't right.
Only a very limited number of those people really know enough to extract all of the qualities out of the parts.
Mostly THOSE are the people with an open mind. And the guts to investigate a claim, or a spec, or a phenomenon.
And the guts to draw the right conclusion, whether they like the outcome, or not.

- You too, you run after OPA627 community. This opamp is not as good as everyone wants to believe. Its sound is colored. Why? I don't know, never deeply investigated. But I had to dismiss it because of this. Ever heard it side by side with the AD797? A tricky opamp, hard to get stable (you need 600MHz or 1Gs/s scope), but very, very good when used properly. Which only VERY few people do!

- Especially do not believe companies. They need to sell.

- All batteries sound different. Are you listening to your opamp or to your battery? Or your bypass caps? Multilayer ceramics? Slow electrolytics? Are you hearing the dielectric properties of a chemical substance?
Run on batteries, listen carefully, change your electrolytics, listen again, you'll hear differences. Shouldn't be possible, if batteries were perfect.
Batteries are helpful, not holy.
Pick up the power supply line with a decent series capacitor (ground reference at input of that same device (lynx?)), feed it to a microphone amplifier and listen to it when your gear is working. You hear music. On the power supply lines.

_ Not all that is not the best is bad. I never said that. Compared to a OPA2604 indeed a 2134 is not bad, even slightly better maybe.
But compared to a REALLY good opamp the 2134 is bad. Not "fair". The difference is big.
It is all about perspective. The moment you know how REALLY good something can sound, the differences become VERY apparent, and big gaps between opamps become clear.
Look back 8 years. Remember what you thought was top quality back then. Is it still that good? Or has your knowledge and experience advanced? This is also an illustration in how far you yourself have advanced.

-Award winning audio gear does not tell me much, except for that they did a good job in implementation of mediocre stuff, and achieved a (slightly?) better balance than others. That's an art, and I have high respect for those people that make a successfull product on sound quality merits. I work with this award-winning stuff all day, design award-winning stuff myself and know how gross those claims can be.
Award-winning audio / hifi is about things that sound "pleasant".
I won't degrade Lexicon. They need to earn a living too. Nothing wrong with that, but budget is budget. If the OPA2134 is good enough for the price, then they CERTAINLY will not put a more expensive opamp in!

-You're right about the distortion figures in the THS datasheets. I did not read carefully enough, I take that back.
The THS 4062 and THS4032 seem to have quite similar distortion figures. Above 100kHz. Below that, there is no data, unfortunately. 3rd harmonic for 4032 is better below 1MHZ and worse above 1M but that's due to the difference in speed (is it? see below), and not so relevant for audio, I suppose.

-But the input voltage noise of the two tells another story. In I/V converters not very important, I agree, but in all normal audio-applications this is VERY important. Here all noise counts and colors your signal 9 times!

-About speed: The 180MHz of the THS4062 is somewhat flattered: only in non-inverting mode, gain +1. Being a unity gain stable voltage feedback opamp, that will be half (I.E. 90MHz) at double gain (+2). THS4032 is 100MHz here.
In an I/V converter the opamp is inverting. So, also here the tables have turned. Because the THS4032 is somewhat decompensated (and hence not unity-gain stable) it is 100MHz (@G=-1) where the 4062 gets stuck at 50MHz.
So essentially in all areas the THS4032 is faster, except at G=+1, which it can't do...

-About settling time: The single most important feature for I/V converters. What happens to your audio signal when the square wave is ringing? There is a lot of energy generated in ringing, it is fed back by the feedback network right into your dac's output!...which is all translated in audible disturbances, noise modulation, coloration, power supply modulation, ground modulation, reference voltage modulation, and what else.
When an opamp stops ringing halfway compared to the other type, that means half (okay, 65% in this case, 90vs140ns) the time duration of unwanted energy.

-No we do not evaluate sound by the datasheet. But the datasheet is a very interesting (although complicated) source of information from which we can make the assumption if a part has potential or not. And if settling time, noise and the like sport good figures, then we can assume that the opamp has potential.
The other way round: If I have tried an opamp, and I found it to be sounding very good, then I like to blame some good specs for that. However I admit that that's quite unscientific. But if you have a lot of experience, then you can (I can at least) see from a datasheet if an opamp will be worth trying or worth to be left alone.

-Burr Brown do anything to optimize their specs. Nothing wrong with that. But that does not say ANYTHING about sound quality. At Ti they do not evaluate opamps nor dacs for sound quality. They want a part to be technically correct. Specs correct. Reproducability optimized. Ofcourse.

Re. Lynx: Okay if you say so. I can't believe that. Is it used in an electrically clean environment? Or in a computer?
Did you do broadband measuring (0Hz-100/200/300/1000whateverMHz) of your supply lines and ground? What will be the PSRR of your opamps and other chips on this card at 10MHz? and at 100MHz? How much of this pollution will get into your audio path, and ground path, and reference voltages? What will that do? Nothing? because it is 100MHz? It will be half rectified by all kinds of semiconductors in your chips, stored in parasitic capacitances, released a little later, generate offsets, modulate or be modulated by your audio signal, generating all kinds of intermodulation products, noise modulations etc etc. There you go: polluting your sound.

-You make an assumption that is very peculiar:
"The reason why I couldn't hear the difference was in the fact, that the spectrum of distortions hasn't changed with op amps swap."
How do you know? Where is the proof of the correlation? It is only a convenient explanation which unfortunately has the power of making you stop thinking.
This surely can't be the end, can it?

There are two things you know: 1. the distortion spectrum did not change, and 2. the sound did not change.
This is totally insufficient to draw ANY conclusion from, otherwise than that apparently the things you actually DID measure, appeared to have not changed.

Try listen to decent loudspeakers. That is a lot more revealing. You need to develop a sound field in front of you where subtle phase- and time differences an low-level information take care of proper stage display, front-to-back stage/hall info, placement of instruments in the available space, etc. Headphones do not give you (all of) those clues. It all happens inside your head, which is a very unnatural thing.

Re.: my Juli@: you'll be surprised how good those AKM's sound. I was surprised too. And I already had a hint, because of the Yamaha. Again you're fixed to specs 'n data. I'm not. I listen to my own recordings of symphony orchestras in real concert halls and relate the sound quality to actual music from which I know how it actually sounded in the hall!

To "temporary":
Evidence is unstable. Correlation fails. RMAA is measuring static data. Good for providing static specs.
But useless for obtaining relevant info on sound quality. That relies on dynamic behaviour of the active parts like A/D's, DACs, opamps. RMAA does not measure any dynamic property. For example: why not make a 20Hz-20kHz sweep at -1dBFS and do an uncorrelated amplitude sweep from -50...-130dB at various frequencies, and look at the intermodulation products and amplitude linearity results? Or the other way round; an amplitude sweep between 0dBFS and -130dBFS of a range of frequencies, and run a frequency sweep at the same time at -40, -50, -60, -70, -80, -90, -100 etc dB... what would we see? I don't know but would for sure be interesting, don't you think?

If you hear differences in sound, you may or may not see differences in test- and measurement results.
But who is telling you that those are correlated? What evidence would you provide to show beyond any scientific doubt that the things you have measured are indeed exactly the same things that cause the differences in sound you hear?

This is the heart of the problem: it is impossible.

For now, the evidence is absent, and we have to rely on our own judgement.

That is what makes sound quality so interesting...and so controversial.

Gordon: Why did Crystal design the CS43122 if they already had the 4396? The only difference is 2dB in dynamic range (as far as I see).
To me it is the same chip in another package, maybe with 1 slightly thicker ground wire from die to pin18, or 1 bit more in the modulator, like 5bits for CS43122 and only 4bits for the CD4396? Maybe you know?

Temporary: Stereo crosstalk is greatly improved by all actions described in previous postings.
It is not attribuable to one single source. Depends mainly on quality of board layout, thickness of copper tracks and ground impedances, power supply decoupling, and clock, these factors determine if it is digital crosstalk or analog.
Especially digital crosstalk is not to be overlooked: digital transitions all over the place create noise on power lines and "ground bounce"; and that noise generates jitter everywhere, which is modulated by your audio signal. This "data-jitter" modulates the clock frequency around your dac and your crosstalk is a fact.
Take care of a very good clock, and decouple all power supply pins and reference pins of all chips -analog as well as digital- with 100uF minimum high quality electrolytics (Panasonic FC or Sanyo's Oscon or equivalent stuff) AND high-speed surface-mount capacitors with low-dielectric absorption properties. NO ceramics! Better use 0805 or 1206 PPS film, widely available nowadays from Panasonic and Epcos, to name a few.
Block incoming RF, by using good common-mode inductors in power-supply feed lines as well as ground that is coming from your computer ground plane.

With these measures you will greatly decrease dynamic crosstalk, and you'll end up with a much wider and much more transparent sound field.

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