Quote from: krabapple on 2014-12-02 17:30:22

That warm tubey goodness (which I have heard)  only was audible with music when the system was biamped.    And only when he used speakers that were a tough load.  You left that part out.  IOW, you have to 'match' your tube amp to the 'right' system to get that sound*. Meyer talks about this too, in another part you didn't quote.

No, I didn't leave anything out.  I provided an exact cut out of the article with the complete answer.  Here is the concluding paragraph for the whole article:

Now AMir, you know and I know know and everyone who can see knows that this is nto the screencap you posted before

The conclusions as he states them is quite different than our marching orders in forums. Have someone say they replaced an AVR with a monoblock and heard a difference and hell will break lose. The person will be told that is an impossibility. Yet, above is your expert witness saying that could happen.

And this is what he says above that concluding remark:



This torpedos any statement that amplifiers sound the same.  That even if two amps have been shown to sound the same in blind tests, all you have to do is change the speaker and the sound will be different. 

Audiophiles we hate talk about this all the time.  They call it "synergy."  Here is your expert witness saying that is 100% true.

Might be on your next pop quiz.  Better read up on it.

Quote from: krabapple on 2014-12-03 03:24:12

Might be on your next pop quiz.  Better read up on it.

Since you liked my last quote , here is another from Mr. Meyer's article:

.

And this is what he says above that concluding remark:



This torpedos any statement that amplifiers sound the same.  That even if two amps have been shown to sound the same in blind tests, all you have to do is change the speaker and the sound will be different. 

Audiophiles we hate talk about this all the time.  They call it "synergy."  Here is your expert witness saying that is 100% true.

Being a “statement” product, the Mark Levinson No 53 sports a traditional linear power supply from the Mark Levinson Reference 532 amplifier. The temptation in class D designs is to use a switching mechanism in the power supply itself feeding the amplifier. While this provides improved efficiency it aggravates a weakness of switching amplifiers which is their very high sensitivity (compared to linear amplifiers) to power supply voltage variations and noise which unfortunately get worse with switching supplies. Copious amount of “negative feedback” can be used to compensate for this but that leads potentially to amplifier instability (and some would claim compromised audio fidelity). [/i][/color]

Are you able to follow this kind of technical explanation...?

tsk, tsk, Amir, another line taken out of context.  You're incorrigible.  In context of what's written *before and after*, that one-line answer makes a lot of sense.  Cherry-picking is a form of  cheating. 

That answer isn't meant to stand all by itself -- it comes after pages of explanation where the 'questioner' has been carefully led to a place of understanding.  And it precedes the coup de grace that lays out , carefully qualified, conditions where audible difference likely does and does not manifest in amps.

And it's simply ludicrous to claim it 'torpedoes any statement that amps sound the same'.  In the case where two SS amps under comparison aren't being driven to distortion/stressed by speakers with 'strongly varying impedance curves',Meyer would say, quite correctly and confidently, that they will probably sound the same, with music, in a blind test.  That's torpedo-proof.

And the beauty part is:  it's also a rather far more common case for any two random setups than, say, happening upon an SS amp vs a tube amp as the top halves of two biamped setup (the only situation here where *music* acted as a revealing probe signal)

"music" did not act as revealing probe signal.  A couple of tracks picked at random by a tester does not constitute a proper test.

The problem is Steven, our esteemed member Arny, has proven that high-power solid state amps sound different:

If two amplifiers sound different on pink noise, they are different sounding.  Period.  End of discussion.

Amir, please reveal the means by which musical test tracks were selected for this highly publicized sighted evaluation that you have staked your reputation and the reputation of your business on:

http://www.madronadigital.com/Library/Mark...3Amplifier.html

"Reinventing the Audio Power Amplifier: Mark Levinson No 53"

By Amir Majidimehr

Originally Posted by amirm
The comparison I performed was using a Mark Levinson No360S against the on-board DACs in five to six DVD-A and SACD players, all playing the same time sync'ed CD. In other words, I would listen to the analog output of the player while its digital output would feed the ML DAC. All front panel lights were turned off in addition to video circuits (yes, all of that made a difference in fidelity).

The two sources were fed to the dual inputs of a Stax "earspeaker" electrostatic headphone amp. If you are not familiar with Stax, you can read learn more about them here: http://www.stax.co.jp/Export/ExportProducts.html. I have three of their units and results are consistent across the board although the highest end unit does make the job a bit easier. Using headphones allowed me to completely eliminate the room and take advantage of the amazing transparency of these headphones to listen for the slightest differences. To latter point, I would often listen to material at levels well above what I would use for listening to music, allowing me to hear detail that would otherwise be lost.

I then picked material that made it easier to detect differences between DACs. I am not going to disclose what constitutes such content. Without such material, the job can range from difficult to impossible. One has to know what could be damaged by a DAC and then use music that has such content. To give you an example, when you compress music, it is the transients that suffer. So something like guitar music is much more revealing than say, violin as the latter is much more harmonic than the sharp impulses of a guitar. Voices play the same role. None of these are useful for testing DACs though so don’t use that as a hint to the question posed . You can’t test the cornering of a car if you just drive it straight….

The comparison was then conducted without knowing which input is which, sitting in front of the headphone amp and toggling back and forth. When necessary, I would go back and re-listen. Once I found which one sounded worse, I would then repeat the exercise by randomizing the inputs and seeing if I could still identify which one was worse. My success rate was 100% in the second test (i.e. could always verify that the first result was not by chance). This testing was repeated a number of times comparing the different sources against each other and the ML.

I did not level match anything. However, once I found one source was worse than the other, I would then turn up the volume to counter any effect there. Indeed, doing so would close the gap some but it never changed the outcome. Note that the elevated level clearly made that source sound louder than the other. So the advantage was put on the losing side.

The results above were later objectively shown to be backed by some science in Stereophile magazine. In reviews of said players and Mark Levinson, it was shown that the former would only resolve to 14 or 15 bits of audio samples. Turning off the front panel pushed some up to 16 bits or so. The ML on the other hand, was tested to have equiv. of 19.5 bits. This is contrast to all the DACs being rated at "24 bits."

Now this testing is a few years old (probably circa 2001 to 2002). Maybe DACs have improved so much that the $20 part in the player is just as good as my then $8000 Mark Levinson DAC (which was hand tuned). If so, then I like to know who has tested the new ones and details of their methodology.

There you have it. Was it worth the wait?

Quote

And the beauty part is:  it's also a rather far more common case for any two random setups than, say, happening upon an SS amp vs a tube amp as the top halves of two biamped setup (the only situation here where *music* acted as a revealing probe signal)

"music" did not act as revealing probe signal.  A couple of tracks picked at random by a tester does not constitute a proper test.

If two amplifiers sound different on pink noise, they are different sounding.  Period.  End of discussion.  This is not a place where one hides under that excuse.  For pink noise to garner nearly 100% confident differences in double blind testing, as they did in Meyer's testing, one or both amps are deviating from anything that we would envision a linear amplifier to do: add gain without any colorations.

Quote from: amirm on 2014-12-03 14:28:24

Quote

And the beauty part is:  it's also a rather far more common case for any two random setups than, say, happening upon an SS amp vs a tube amp as the top halves of two biamped setup (the only situation here where *music* acted as a revealing probe signal)

"music" did not act as revealing probe signal.  A couple of tracks picked at random by a tester does not constitute a proper test.

Music is what most people listen to over their audio systems.

Most people, if they could hear a difference  with a test tone, but not with music,  wouldn't care about the former.  They'd care if they could hear it with music, though.  But you're special, I know.

Quote

If two amplifiers sound different on pink noise, they are different sounding.  Period.  End of discussion.  This is not a place where one hides under that excuse.  For pink noise to garner nearly 100% confident differences in double blind testing, as they did in Meyer's testing, one or both amps are deviating from anything that we would envision a linear amplifier to do: add gain without any colorations.

I see.  So, if difference can be perceived under *some* circumstance, it is perceived in *all*?

You've heard of masking, right? Perception of sonic difference dependent on absence of other sounds?

Also, I'm with you on the 'envisioning a linear amplifier' thing: I would call that tube amp's behavior *intentionally pathological*.  And again, no one here, or elsewhere, is claiming that tube amps fit the definition of 'amps that are likely to sound the same'.

http://www.madronadigital.com/Library/Mark...3Amplifier.html

"Reinventing the Audio Power Amplifier: Mark Levinson No 53"

By Amir Majidimehr

Amir, hopefully it will be worth our wait when you explain how you ran these amp distortion comparison tests of yours. Guess we'll just have to keep asking.

Quote from: ajinfla on 2014-12-03 16:50:49

http://www.madronadigital.com/Library/Mark...3Amplifier.html

"Reinventing the Audio Power Amplifier: Mark Levinson No 53"

By Amir Majidimehr

Amir, hopefully it will be worth our wait when you explain how you ran these amp distortion comparison tests of yours. Guess we'll just have to keep asking.

Why do you assume that by repeating your question it gets you the explanation?

Why do you assume that by repeating your question it gets you the explanation?

Originally Posted by amirm
The comparison I performed was using a Mark Levinson No360S against the on-board DACs in five to six DVD-A and SACD players, all playing the same time sync'ed CD. In other words, I would listen to the analog output of the player while its digital output would feed the ML DAC. All front panel lights were turned off in addition to video circuits (yes, all of that made a difference in fidelity).

The two sources were fed to the dual inputs of a Stax "earspeaker" electrostatic headphone amp. If you are not familiar with Stax, you can read learn more about them here: [url="http://www.stax.co.jp/Export/ExportProducts.html"]http://www.stax.co.jp/Export/ExportProducts.html. I have three of their units and results are consistent across the board although the highest end unit does make the job a bit easier. Using headphones allowed me to completely eliminate the room and take advantage of the amazing transparency of these headphones to listen for the slightest differences. To latter point, I would often listen to material at levels well above what I would use for listening to music, allowing me to hear detail that would otherwise be lost.

I then picked material that made it easier to detect differences between DACs. I am not going to disclose what constitutes such content. Without such material, the job can range from difficult to impossible. One has to know what could be damaged by a DAC and then use music that has such content. To give you an example, when you compress music, it is the transients that suffer. So something like guitar music is much more revealing than say, violin as the latter is much more harmonic than the sharp impulses of a guitar. Voices play the same role. None of these are useful for testing DACs though so don’t use that as a hint to the question posed . You can’t test the cornering of a car if you just drive it straight….

The comparison was then conducted without knowing which input is which, sitting in front of the headphone amp and toggling back and forth. When necessary, I would go back and re-listen. Once I found which one sounded worse, I would then repeat the exercise by randomizing the inputs and seeing if I could still identify which one was worse. My success rate was 100% in the second test (i.e. could always verify that the first result was not by chance). This testing was repeated a number of times comparing the different sources against each other and the ML.

I did not level match anything. However, once I found one source was worse than the other, I would then turn up the volume to counter any effect there. Indeed, doing so would close the gap some but it never changed the outcome. Note that the elevated level clearly made that source sound louder than the other. So the advantage was put on the losing side.

The results above were later objectively shown to be backed by some science in Stereophile magazine. In reviews of said players and Mark Levinson, it was shown that the former would only resolve to 14 or 15 bits of audio samples. Turning off the front panel pushed some up to 16 bits or so. The ML on the other hand, was tested to have equiv. of 19.5 bits. This is contrast to all the DACs being rated at "24 bits."

Now this testing is a few years old (probably circa 2001 to 2002). Maybe DACs have improved so much that the $20 part in the player is just as good as my then $8000 Mark Levinson DAC (which was hand tuned). If so, then I like to know who has tested the new ones and details of their methodology.

There you have it. Was it worth the wait?[/i]

Originally Posted by amirm

Quote

Originally Posted by Terry Montlick View Post

And you derive this probable number from exactly what statistical test??

Nothing that complicated. I give it one out of three chances to be wrong, based on more than a decade of conducting double-blind and subjective tests and formal evaluations of my hearing. In other words, I know what percentage of time I have made a fool of myself in such tests . Versus being right.

You didn't answer my question on how many blind tests you have been involved in.

No, two tracks does not equate "music."

You must demonstrate that those two tracks are revealing of frequency response variations which is what he has testing.  His data clearly shows that pink noise did that and his selected music clips did not.  We have objective data here on which is the right answer: it was the pink noise.

So their is precedence and ample reason to continue asking about your (ML) amp distortions audibility test, in the Audibility of Audio Power Amplifier Distortions thread.
I'm (we?) hoping it doesn't take 2 threads and 400+ posts to shed light on your amp "tests", but that's entirely up to you.

I was looking at the Levinson 57 power amp pictures on the web and suddenly realized that a pair of them grace the pictures of his personal stereo system that Amir has posted on AVS.

Explains a lot, eh? ;-)

He's not a music lover/audiophile himself, he simply sees a market for and sells audiophile (vs "Mid-Fi") equipment.

Careful now, Arny. If you mention his name three times he'll appear just like in the movie Candyman.

He claims to have a laptop at home where he analyses files.

Mentioned something about a real time spectrum analyzer once, but I don't recall the details.

The above is where the money is dear Ammar.

Quote from: ajinfla on 2014-12-04 13:09:10

He claims to have a laptop at home where he analyses files.

You don't think I have one Ammar?

Quote

Mentioned something about a real time spectrum analyzer once, but I don't recall the details.

Happy to provide you detail.  Here is my setup for the comprehensive measurement of digital audio in AVRs and Processors:



cheers,

AJ

Amir, I have never ever doubted you having spectral analysis capability on your home laptops.

I was just curious about the specific program used concurrently when running those "Hi Re$" ABX test files is all. Thanks for those details shown anyway.

Now of course, that brings us no closer to how you did your ML 53 vs .....amp distortion audibility comparisons.

We certainly know how you did DAC comparisons