Thanks. These kind of tests are time consuming to set up and so its good to know they are appreciated.
No rush
Your STAX is too good for your speaker
Seriously, I usually rely on my speaker more than my Sennheiser, but in this test my newer speaker just couldn't do it better than the headphone so I modified the speaker. Haven't tried it again with the modified speaker but I think I know why the speakers lost its "ears".Why not. I think nowadays opamp chips are not expensive so why choosing affordable chip for the sake of price. Choose OPA2134 instead. Statistically this opamp satisfies more listeners than NE5532.
Start with Statistics, if in doubt.
This is the right way to do it. I think (I should say I believe, or I'm sure, because I have done this) with such a controlled test I can pass the ABX quite satisfactorily with these opamps. But if you look at this carefully, there is no finite boundary between "can hear it" and "cannot hear it". I'm pretty sure that many can hear it, but their performance in ABX will be too bad for most of you to believe it.
Many will appreciate it (well, I for sure learn a lot from every test). If not today, it could be later, as this information stays in the website.
First off, thanks to Mooly for setting it up and providing the results. It's good fun, and a useful discussion.
If anything, the conclusion you can take home is that op amps are pretty hardy beasts, and will perform quite well under the grimmest conditions. I suggest you should probably leave it there.
Let's try an analogy: would you evaluate a 300B SET amp tied to a 3 ohm, 60 dB/W speakers? I mean, you would certainly be able to "hear" the amp under those conditions, but only because you have made it scream.
To the extent that op amps "sound" of anything, it depends on their application and environment. If you want to use an op amp as a unity gain buffer while driving <500 ohm loads, then these results are relevant to your interests. At different source impedance, different loading, and different gain settings, and even different power supplies, each of these op amps is likely to sound (and perform) differently and this test is not indicative of that performance in any way.
There's no magic here. Even at the most basic level of output noise and distortion, it's a textbook exercise to show how these quantities vary with input impedance and load, respectively.
Know your application and read the datasheets carefully. That's how you select op amps.
If anything, the conclusion you can take home is that op amps are pretty hardy beasts, and will perform quite well under the grimmest conditions. I suggest you should probably leave it there.
Let's try an analogy: would you evaluate a 300B SET amp tied to a 3 ohm, 60 dB/W speakers? I mean, you would certainly be able to "hear" the amp under those conditions, but only because you have made it scream.
To the extent that op amps "sound" of anything, it depends on their application and environment. If you want to use an op amp as a unity gain buffer while driving <500 ohm loads, then these results are relevant to your interests. At different source impedance, different loading, and different gain settings, and even different power supplies, each of these op amps is likely to sound (and perform) differently and this test is not indicative of that performance in any way.
There's no magic here. Even at the most basic level of output noise and distortion, it's a textbook exercise to show how these quantities vary with input impedance and load, respectively.
Know your application and read the datasheets carefully. That's how you select op amps.
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Husky Voice
Here are 2 opamps (red and violet). One of the opamp produce the very husky voice of Mark Knopfler on the "You walk out on a high wire", while the other one just too lean. No matter how you change the amplitude or add various controls to the test, you cannot change the tonality.
Here are 2 opamps (red and violet). One of the opamp produce the very husky voice of Mark Knopfler on the "You walk out on a high wire", while the other one just too lean. No matter how you change the amplitude or add various controls to the test, you cannot change the tonality.
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WTF !.
Anything say 6/8 or better means that you are picking up fine differences......concentration span/boredom etc factors into the equation/results.
10/10 or 8/8 means an unequivocal result in my view.
The importance of the sonic differences to the average listener is another subject altogether...hell, I do very much of my listening to spoken word AM radio but even with such a source I can easily tell differences between transmitters relaying the same content.
With such AM sources I can also easily hear differences wrought by the likes of BQP.....don't shoot the messenger please.
Dan.
I just came home from work in a very tired condition. When I listened the husky vocal in training mode I made no mistake. I did it several time (with no mistake, more than 10x for sure) until I was sure that I will not make mistake in the test mode. Then I hit the "Begin Test" button and that's the result.
You are correct about the 6/8.
The reason I compared TL072 and TLE2072 was because I had a feeling that these 2 opamps had the biggest sound difference (in fact, I had no mistake in differentiating Mark Knopfler's husky voice either in ABX test mode or training mode). And because I have put TL072 on the top of my preference list and TLE2072 on the bottom of my preference list.
I'm a believer in amplifier topology and simplicity (see attachment).
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Not bad at all. After looking at the PDF, I actually believe in the quality of this chip more.
From my experience, and also from the listening tests (thanks Mooly), I found that the problem with sound has high correlation with an existence of undesirable distortion, and this undesirable distortion seems to correlate with high frequency, either intermodulation or very high order non-linear distortion.
CFB versus VFB for example, has trigerred a hot debate. But the fact is that everybody agree that CFB has better high frequency performance. It is just that less people realize how important the HF performance is.
NE5532 for example, if I'm not mistaken, has a not favorable THD above 6kHz. I think this could be the reason I found it fatiguing, while the general performance is outstanding. But then I will be happy to use NE5532 for bass duty, or before the AD conversion stage.
Here's TL072 superior THD at HF (see attachment). I believe NE5532 is not as good as this??
ADD:
The THD for TL072 is minus the noise (which is not so good), but the point is the non-linear distortion is flat up to 10kHz and more. Noise is not so disturbing imo, and to implement this chip I think the circuit should have a very good/low power supply noise.
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Jay, you read a different CFA debate than I did then
some don't think CFA brings any useful "magic" to audio frequency reproduction - a decade ago you couldn't mention CFA at diyAudio without a guru telling you he and his customers universally found it sucked for audio
I don't go that far - never really make such broad subjective claims - just examine the circuit theory, datasheets and compare with the smattering of Psychoacoustics I've picked up over the decades of hobby interest
but I do find the recent CFA enthusiasm here heavily fanboyish - not mature circuit analysis, over claiming credit for circuit techniques that are not CFA specific, vilifying people trying to simply bring balance and perspective to the discussion
I have made really excellent technical performing composite amps with TL072 input (a least for cheap prototyping, debugging) and several different full complementary bipolar semi process modern monolithic VFA as well as CFA buffer/output amp stages
some don't think CFA brings any useful "magic" to audio frequency reproduction - a decade ago you couldn't mention CFA at diyAudio without a guru telling you he and his customers universally found it sucked for audio
I don't go that far - never really make such broad subjective claims - just examine the circuit theory, datasheets and compare with the smattering of Psychoacoustics I've picked up over the decades of hobby interest
but I do find the recent CFA enthusiasm here heavily fanboyish - not mature circuit analysis, over claiming credit for circuit techniques that are not CFA specific, vilifying people trying to simply bring balance and perspective to the discussion
I have made really excellent technical performing composite amps with TL072 input (a least for cheap prototyping, debugging) and several different full complementary bipolar semi process modern monolithic VFA as well as CFA buffer/output amp stages
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Yep, exactly the sort of stuff expected.
Mooly,
I think a complete rewind and reset is in order with new recordings. Otherwise Jay's fantastic comments are worthless.
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