John Curl's Blowtorch preamplifier part II

[john curl]

As I said, Joshua, 'intellectual honesty' If I can't prove anything completely, then I am intellectually dishonest to even bring it up. OK, Jan.

[PMA]

The point is that some contributors expect that if we cannot measure and prove a phenomenon by current methods this phenomenon does not exist.

[janneman]

Originally Posted by PMA

The point is that some contributors expect that if we cannot measure and prove a phenomenon by current methods this phenomenon does not exist.

Wrong. It would mean that we don't know what it is or how it is caused. Condemnation without Examination is Prejudice, both ways.

jd

[PMA]

On the other hand, if we measure something in a less traditional way, like RF contamination, it is marked as unimportant. "Show me the influence in audioband (under 20kHz)", is the answer, of course by spectrum analysis. We are permanently forced to prove by routine approach. If we quit routine approach, the results are unimportant or inaudible. Stage 2.

[janneman]

Originally Posted by PMA

On the other hand, if we measure something in a less traditional way, like RF contamination, it is marked as unimportant. "Show me the influence in audioband (under 20kHz)", is the answer, of course by spectrum analysis. We are permanently forced to prove by routine approach. If we quit routine approach, the results are unimportant or inaudible. Stage 2.

Wrong again. What we (or at least I) ask is: can you give some good, reliable proof that indeed this audible difference you claim to hear from RF influence, does a) exist and b) is the result of the RF.

Nobody says it cannot exist.

You really need to read better.

jd

[PMA]

The null test must be performed on a complete system. I.e., it has no value to test e.g. a link stage only. Different HF content on outputs of 2 link stages may have great influence on power amp behaviour. So do cables. I encourage anyone to perform a null test on a complete audio chain, with power amps and speakers. I can imagine excuses that it is difficult to perform.

[Edmond Stuart]

Originally Posted by 1audio

The point I was making about the reference to the piano tuning was that a harmonically correct distortion that should sound like normal instrument harmonics may actually not correspond to the real sound and to a sensitive listener may sound "wrong".
[snip]

Hi Demian,

Under the assumption that you are talking about 'stretching', I'm afraid you missed the point. It's just the opposite. Inharmonicity -instead of harmonicity- is percieved as wrong.
'The tuner will stretch the notes, slightly sharpening the high notes and lowering the low notes so that the overtones of low notes have the same frequency as the fundamentals of high notes.'
In other words, the purpose of stretching is to compensate for (inevitable) inharmonicity of the strings.

Source: http://en.wikipedia.org/wiki/Piano_acoustics

Cheers,
Edmond.

[syn08]

Originally Posted by PMA

The null test must be performed on a complete system. I.e., it has no value to test e.g. a link stage only. Different HF content on outputs of 2 link stages may have great influence on power amp behaviour. So do cables. I encourage anyone to perform a null test on a complete audio chain, with power amps and speakers. I can imagine excuses that it is difficult to perform.

Did you do it?

The normal/logical approach in experimental sciences is:

1. You provide the evidence and all required information to reproduce your results. Be prepared for a critical approach and to answer questions.
2. Others are doing their best to reproduce your results. It may be required to answer more questions.
3. You get the confirmation or infirmation of your original results. Theoreticians will jump in, trying to find an explanation for the results.

Expecting somebody to invest and check what you think is relevant will usually not pass the ** filters, unless you have a very solid theoretical background for your assumptions and allegations (ala "the Higgs boson" of hifi audio).

[Joshua_G]

Originally Posted by janneman

Joshua,

You are missing the point of these discussions massively. It is not about whether science has answers or not. It is not about whether PIM or TIM exists or can be audible. That is not contested as such.
The discussion is about answering questions about a statement that is made, about providing arguments that support your position so that others can judge for themselves instead being limited to 'believe' or 'not to believe'. Providing full details of your measurements, so that others can repeat them and either confirm or falsify them.
In other words, intellectual honesty.

jd

Thank you.
Sometimes, certain types of distortion are being heard by some people, though not by all people, and it isn't completely set how to measure it. This have nothing to do with intellectual honesty.

[Joshua_G]

Originally Posted by PMA

The point is that some contributors expect that if we cannot measure and prove a phenomenon by current methods this phenomenon does not exist.

This is what I meant.