John Curl's Blowtorch preamplifier part II

[SY]

Originally Posted by john curl

Now, what about quality hi end design? Does it work? Well, it seems to work for the reviewers and customers that we associate with, and that is all that counts. Who cares if some 'scientist' somewhere discounts our efforts, let interested audiophiles decide.

You've illustrated my point better than I could.

[Wavebourn]

Right; and sockets and connectors made to looks the same not always work the same. Cargo cult. But it is not about magnetic properties. It is about contacts. John already mentioned bi-metal wires, where still core was surrounded by thick layer of copper. It works well, despite of magnetic material used, because each of 2 metals serve own function: steel for mechanical stability, copper for electrical conductivity. But when layer is thin, and it is plated, things are different.

[KBK]

Originally Posted by jcx

the bare fact of a physical mechanism like magnetic material hysteresis isn't however an explanation of the audiophile recommendation to avoid magnetic materials in circuits

as a precision instrumentation designer, having read extensively on the subject of analog circuit design for precision applications over a 30 year career I have never seen mention of steel core component leads, resistor end caps as a limitation to at least -120 dB on measured distortion products in low level analog circuitry

I recall one reference to Ni plated connectors giving -130? dB distortion products in kW RF connectors

there are several accounts of magnetic field leakage from air core inductors interacting with steel chassis, ect giving measurable distortion so I suppose you could "see" magnetic component leads in the leakage path of an inductor - so we have one avoidable condition that may have measurable effect
Bruce Hofer related an anecdote that the steel lid did give some measurable distortion in an AP analyzer's oscillator circuit - not wanting to give up on the external magnetic field shielding they added a thin Al plate to the inside of the lid over the sensitive circuit and the Eddy current "shielding" was enough

I don’t recall Williams, Edgar mentioning “magnetic” resistor leads as a limitation in their designs of ultra low distortion audio oscillators


and of course there is the further logical conundrum of transformers and electrodynamic drivers often at both ends of the recording process with clearly measurable distortions from magnetic material nonlinearity
with our analog circuitry with basically immeasurable effects from magnetic component leads in the middle

it would be far more convincing if there were actual measurements showing these hypothesized "audible" magnetic component leads, endcaps, connector plating distortion (IM too) magnitude, spectrums...

the answer comes when you look at the ear/brain as a system.

The ear does not care that the distortions are so low in level. The ear does not work on or in engineering terms or logic weighting.

the ear hears sum total values, nothing more... and certainly nothing less.

So the 100-130db down 'distortions' are not on the bottom of the signal... 'swamped', at all.

To the ear, the distortions shift the peak values about, in the micro domain, and are thus heard by the ear.

It truly is that simple.

A case of improper weighting and improper analysis.

[wrinkle]

Originally Posted by janneman

This is utter nonsense Ed. It is well known that differences in fingerprints is a statistical issue. The chances that two fingerprints from different persons match to a specific degree are very small but not zero. Once in a while two DO match, with unfortunate consequences for the innocent person.

DNA differences are much more pronounced, but you can just wait for the case that an innocent guy/girl gets hanged because he /she was unfortunate enough to have the same DNA (within the bounds of detectability) as the real offender.
Another reason not to hang people.

jan

DNA differences are only true for some portions of the chromosome, and if there is contamination from other species there may be uninteded lines that confuse the matching a lot, and then there is the errors in multiplication used to get enough out of very small samples.

[jneutron]

Originally Posted by ThorstenL

Most scientists and those who profess a supposedly scientific world view categorically arrogantly deny such a possibility, which is highly unsafe given the history of science.

I enjoy a rather large set of scientists, physicists, and engineers with whom I have the pleasure of working with around the world, most of them among the best in the world.. And absolutely NONE of them have attributes consistent with your assumption. NONE...



It is a romantic notion to believe that the "scientists" believe such sillyness, but it is not accurate. Please refrain from characterizing large groups of people so incorrectly.

j

[simon7000]

Originally Posted by janneman

This is utter nonsense Ed. It is well known that differences in fingerprints is a statistical issue. The chances that two fingerprints from different persons match to a specific degree are very small but not zero. Once in a while two DO match, with unfortunate consequences for the innocent person.

DNA differences are much more pronounced, but you can just wait for the case that an innocent guy/girl gets hanged because he /she was unfortunate enough to have the same DNA (within the bounds of detectability) as the real offender.
Another reason not to hang people.

jan

Jan,

In this country it is the PERCEPTION of perfection by judges and juries that matters. People have been hung, shot and otherwise thrown in prison because of the perception that fingerprint evidence is absolutely foolproof. That case where all of the experts found 15 or more points of agreement changed the way the issue is now handled.

Texas kills a couple dozen folks per year (Sometimes more sometimes less.) Now what perception of the evidence do you think has been used in many of those cases.

As to the death penalty, there actually are a few cases where it seems reasonable. (21 years for mass murder seems to most too little.) Around here it costs more in legal fees to get to an execution that it would cost for life imprisonment. So ignoring the error rate issue, which is a political sticky issue, I argue that prison guards can use the pay better than lawyers!

So why are you arguing facts when you know it is perception!

[SY]

Nonetheless, Ed, this has nothing to do with science, everything to do with politics. So put it away.

[KBK]

Originally Posted by jneutron

I enjoy a rather large set of scientists, physicists, and engineers with whom I have the pleasure of working with around the world, most of them among the best in the world.. And absolutely NONE of them have attributes consistent with your assumption. NONE...



It is a romantic notion to believe that the "scientists" believe such sillyness, but it is not accurate. Please refrain from characterizing large groups of people so incorrectly.

j

I put that one back on you John. (not directly, mostly so others can hear the debate aspects being voiced)

As in, millions of audiophiles can't be wrong. Misinformed, mis-educated, unaware, not really understanding the complexities of the physics involved; but they know what they hear, and ~that~.... is not wrong.

It is well beyond subjective, as it is relational and comparative across a large cross-section of people, with repeatable accuracy, regarding their ability to relate information/data... to one another.

It is simply not well framed in terms of logical methodology of physics research.

And that is not a crime, nor is it in error. It is merely a situation requiring a relational bridge.

[john curl]

Well, I have worked with a few physicists and engineers too, over the decades. So what?
What works is what is, not proofs due to measurement, perhaps too subtle for easy and consistent results. I have put forth conclusions of 'what works' from work 10-20 years ago. IF they did not work, we would not continue them, no matter what the 'story'. Why, for example, is the Vendetta Research phono preamp so appreciated, even when it has not been made for 20 years? Maybe we did 'something' right?

[jneutron]

Originally Posted by KBK

I put that one back on you John. (not directly, mostly so others can hear the debate aspects being voiced)

As in, millions of audiophiles can't be wrong. Misinformed, mis-educated, unaware, not really understanding the complexities of the physics involved; but they know what they hear, and ~that~.... is not wrong.

I said nothing about audiophiles.

I said the characterization of scientists given was incorrect.

Nothing more....nothing less.


j