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John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
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Old 2nd March 2011, 06:43 AM   #10341
jan.didden is offline jan.didden  Europe
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Originally Posted by john curl View Post
[snip] The same problem can be found even better by listening to the 30ips full track master tape vs a digitized version of the same master tape by just adding the AD-DA converter to the output of the master tape recorder. You know, A or B. Here, ONLY the digital problems are ADDED. Please everyone, try before you decide.
There is at least one well documented test that tried to show this, the (in)famous Digital Challenge with Stanley Lipschitz and Ivor Tiefenbrunn. The full story is on the Boston Audio Society website.
They inserted or bypassed a Sony F1 PCM in the source line. The change was inaudible, until at a certain point Lipschitz noted that there was a slight difference in noise level between the two situations (the F1 had a higher noise floor). Once he realized that, he scored 100% there after. But the others, inclusing Mr Tiefenbrunn, who relied only on the difference (if any) in the music, scored no better than chance.

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Last edited by jan.didden; 2nd March 2011 at 06:47 AM.
 
Old 2nd March 2011, 08:38 AM   #10342
Telstar is offline Telstar  Italy
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Originally Posted by john curl View Post
It is NOT distortion, it is in spite of some audible distortion.
Exactly.
It's the lack of damage done by A/D and D/A, plus several mastering manipulations (dynamic compression not being the worst offender).
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Old 2nd March 2011, 11:04 AM   #10343
Soundminded is offline Soundminded  United States
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Originally Posted by janneman View Post
There is at least one well documented test that tried to show this, the (in)famous Digital Challenge with Stanley Lipschitz and Ivor Tiefenbrunn. The full story is on the Boston Audio Society website.
They inserted or bypassed a Sony F1 PCM in the source line. The change was inaudible, until at a certain point Lipschitz noted that there was a slight difference in noise level between the two situations (the F1 had a higher noise floor). Once he realized that, he scored 100% there after. But the others, inclusing Mr Tiefenbrunn, who relied only on the difference (if any) in the music, scored no better than chance.

jan didden
Exactly as expected. ALL electrical processing will add some noise to a signal. In this case it surely adds no more than was added to the original tape by the recordeing process to begin with which means that had a digital tape recorder been substituted for the analog recorder, the total noise including the A/D + D/A converters would have been lower than the analog tape recorder alone. Even the added noise is a small price to pay for the elimination of every other form of audible distortion including rumble, acoustic feedback, wow, flutter, harmonic distortion, IM distortion, not to mention pops and clicks inherent in the vinyl record playback system. Had digital recordings come first, vinyl when demonstrated later would have been considered an interesting curiousity but not taken seriously. It would be universally regarded as an anachronistic joke by comparison.

This points out another fact, that the valid audible test for distortions introduced by an electrical signal device whether it is a preamplifier, wire, or A/D + D/A converter combination is not A versus B but A versus A bypassed. How would the blowtorch preamplifier stand up to that test I wonder?
 
Old 2nd March 2011, 01:01 PM   #10344
soundmeister is offline soundmeister  Australia
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Hi John, I understand your points that distortions of higher order (you have explained the importance of 7th harmonic etc) trashing sound.
So, how is it that vinyl sounds better to your ear - can you please elaborate on the differences that you hear between CD and vinyl, and why you prefer vinyl ?.

Dave.
 
Old 2nd March 2011, 01:08 PM   #10345
john curl is offline john curl  United States
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Ivor was a 'fool' to be 'trapped' like that in a listening test that is set up to generate 'null' results, unless one 'cheats'. Ivor has had to live that one bit of overconfidence in his own listening ability for many years.
This is WHY I do NOT do ABX tests. I can't pass them, either. Neither can John Atkinson, or just about anyone else.
Are we deaf, but arrogant? Are we 'fools' to believe in our own listening comparisons? Some here, will tell me so, and more often than necessary. However, I just muddle on, seemingly getting good reviews for some reason, and many happy customers. I guess it is just 'dumb luck' with a few measurements added in.
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Old 2nd March 2011, 01:36 PM   #10346
Joshua_G is offline Joshua_G  Israel
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Originally Posted by john curl View Post
Are we deaf, but arrogant? Are we 'fools' to believe in our own listening comparisons? Some here, will tell me so, and more often than necessary. However, I just muddle on, seemingly getting good reviews for some reason, and many happy customers. I guess it is just 'dumb luck' with a few measurements added in.
No violinist I know of chooses a violin by blind test, neither any pianist nor any other musician.

It seems to me that those people insisting on blind tests don't trust their own listening ability. Possibly some people are fearing Placebo Effect so much that it freezes their listening ability. In reality, Placebo Effect can be neutralized without blind tests, definitely without ABX tests. Possibly, other people deny their listening ability because of it cannot be proved by the scientific means they know.
 
Old 2nd March 2011, 01:38 PM   #10347
john curl is offline john curl  United States
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It is MORE than that Joachim, however idle speculation, here, will not be productive.
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Old 2nd March 2011, 02:09 PM   #10348
pooge is offline pooge  United States
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It seems to me that those people insisting on blind tests don't trust their own listening ability.
If that statement is supposed to be logical, then an equally logical statement would be "It seems to me that those people against blind tests don't trust their own listening ability." Or further, that those people that are against blind listening tests are stressed out ninnies because they are fearful that they won't be able to find differences when there aren't any.

You can accuse people that you don't agree with with any physical, emotional, or mental fault you want. But maybe you should look in the mirror.

It is a mystery to me why some can justify that a test that eliminates all variables except for one is inherently faulty. The pat argument is that the test doesn't do that. The switcher is to "blame". Well simple, get rid of the switcher and move the same interconnect between components. Fast switching is to "blame". Well simple. Don't use fast switching. There is no rule that blind testing requires fast switching. Listen A for a week. Listen to B for a week. SIMPLE!! Is this TOO logical???
 
Old 2nd March 2011, 02:11 PM   #10349
john curl is offline john curl  United States
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I 'warned' you Joachim. Keep up the good thinking, but please don't expose yourself here with it. It causes too much of a problem, because it promotes criticism by others. Many here look for the 'loopholes' rather than the essence of your opinion. Trust me, it happens almost every time I try to say something here.
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Old 2nd March 2011, 02:12 PM   #10350
Joachim Gerhard is offline Joachim Gerhard  Germany
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Do you talk to me or Joshua ?
What really bugs me here is that very few here have constant exposure to a real High End Vinyl Playback System. An old Thorenz or something can not be compared to what is availlable now. If you never heard such a system over an extended period at home you can not judge about it.
 

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