John Curl's Blowtorch preamplifier part II

[john curl]

BV, these subtraction tests are interesting, but they don't seem to be enough. IF they are 'enough' then buy a used Hafler amp and enjoy the audio experience forevermore.
Walt Jung's, Scott Wurcer's and my experience with just a single CAP difference test was difficult to null, even with one of the best IN-AMP's at the time (120dB rejection) and ultra fine adjustment.
I can just imagine the compromises in whole amp difference tests.
What we seem to be looking for is subtle, perhaps near or at the level of perception of sound, yet different enough from other signals to be noted in some way by the ear-brain system by many people of all ages. It is most likely a survival mechanism separating normal environmental sounds from something unusual.
Can I personally prove this? No, not at this time, but it appears to be what is happening.
Should I tell anyone this? Without absolute proof or backup? Well, many here could just happily live in ignorance of what some serious researchers are looking at today. Perhaps, even the mention of such an idea is considered inappropriate, by some. I really don't know, but personally, I would welcome such input, and help contribute to whether it is as important as it seems to be.

[stinius]

Originally Posted by john curl

Why I have to PROVE everything to a bunch of skeptics, who are so insulting as to call me 'intellectually dishonest' or not forthright in my explanations of how to design an amp, is beyond me.

Hi John

I just passing by and haven’t read all posts the last days.

I don’t think you have to prove everything to a lot of sceptics.
There are some people that are more sceptical than others, and if somebody called you what you are saying I hope they regret it.

Hopefully it’s possible to disagree or being sceptical without using such phrases.

Just a question, when you did the tests back in the 70’s, did you do the tests only once or did you repeat the test a number of times and did you do the test with 741’s from another batch?

If you did the test a number of times, did it show the same spectrum?

Cheers
stinius

[Wavebourn]

Come on John... It is a well known fact, about audibility of in-natural sounds. But every time myself, or somebody else expresses this fact, or tries to prove it, or to illustrate on examples, you do everything you can to shut us up, as if you want to be The Single Man Who Saw The Moon, while The Whole World is Against You. It looks like you are knocking hard in already wide open gates.

[anatech]

Hi John,

Demian has completed a test board that we might use together to do some additional measurements, such as the original TIM test.

I have requested the information so that I may also try the TIM test - repeatedly. The way I see things is simple. See if the test can be repeated, then explain the results.

I also have the required equipment to run this test. Is it a case that only people you trust will be trusted with the test details? I mean, it keeps you pretty safe, doesn't it?

Anyway, I have many times stated that I both listen and test. I do hear things I can't test for, never said I didn't. But I always attempt to find a way to quantify what I'm hearing, simply to be able to have a standard that does not change over time as the human subjective experience will. Yet you still take pains to exclude myself and many others here who also listen to their work and hear differences, as well as test with equipment.

So, do you want to show the way? Allow us to test and hear for ourselves what you have heard? These are the real questions here. Once we can reproduce what you have seen, we can discuss the observations more intelligently. Your exclusive nature is not helping your cause, turning possible supporters into people with reasonable doubt.

-Chris

[PMA]

Anatoliy, re-read several last posts of John, please.

[anatech]

Hi,
Does anyone have access to "Intermodulation Distortion in Tape Recording" Robert Z. Langevin JAES July 1963 Vol. 11, No. 2.

It's been referred to as basic material for this discussion by John.

-Chris

[john curl]

Sorry Stinius, while I made the same tests as that presented in the paper, my results were lost in a firestorm in 1991. I doubt that there is anything wrong with the test results, or the 741 IC used.
Maybe, just maybe, any discussion of audio differences is a waste of time. It could well be that the ear imagines things, and that virtually all audio electronics sounds similar, and exceptions have something wrong with them. Of course, I don't know why people come here to deny anything that I talk about, when they could be doing more productive things. I often wonder what I am doing here, myself.
It does appear that if I just disappear from this thread, it goes away. Yet when I try to steer clear of obvious debates in the past, the very same questions and insults come back, by the same people, almost immediately. Why is this? Can't you each have your own thread? Can't each design philosophy be put forth independently, without 'crosstalk' from a skeptic?

[john curl]

Anatech, just look at fig 1, of our paper on TIM. The test setup is there.

[Wavebourn]

Originally Posted by PMA

Anatoliy, re-read several last posts of John, please.

I did. Still, don't understand why John claim people try to deny him, while we are actually trying to support him. Probably, he wants other readers who don't understand what we are talking about, to see this way.

[syn08]

Originally Posted by john curl

Demian has completed a test board that we might use together to do some additional measurements, such as the original TIM test. Demian and I, both, have the test equipment to do the job.

Just curious, what is your expectation regarding these measurements?

Are you ready to disclose the whole setup so that others could reproduce your results?


And have you seen Gerhard's measurements posted a couple of weeks ago? Any comments about?