I'm not aware that anyone has offered to do that. I asked for a back-of-envelope calculation (i.e. an estimate) of the likely source impedance when these issues might become apparent. This is the normal way of approaching a problem in science. It is a useful precursor to a "full theory". If I could be bothered I might do the calculation myself, but the burden of proof lies with those making possibly unphysical claims.mikelm said:
Perhaps you will forgive me if I don't take too seriously someone who, by his own admission, does not claim any particular knowledge of the physics of dielectrics yet presumes to suggest to others that it is "very very complicated" with the implication that they might not understand it. I would rather listen to the people on here who actually do understand dielectrics; curiously, they don't tell me is it too complicated but they recognise that they might have to explain things slowly to someone with enough science background but insufficient recent familiarity with the topic details.
And for those who seek understanding, rather than merely the ability to calculate, there are always the Feynman Lectures. However, I think I saw an admission of a couple of errors in the EM section - not on things which impact audio though.
I have lost count of the number of books on EM I have (it could be approaching double figures - and definitely does if I include books on antennas) but each sheds new light and explains things which the others miss out or gloss over. That may be why I get a bit sharp with people who may never have read an EM textbook yet think they know more than those who have.
I have lost count of the number of books on EM I have (it could be approaching double figures - and definitely does if I include books on antennas) but each sheds new light and explains things which the others miss out or gloss over. That may be why I get a bit sharp with people who may never have read an EM textbook yet think they know more than those who have.
You know I spoke to my good friend Jack Bybee tonight. It was NOT about physics, but about Maigret on TV. We share a fondness for the french detective.
I still use his quantum devices in my audio system, but I can't afford his new stuff. Jack Bybee taught me MORE about atomic physics than I ever learned in college. However, I also did not study 'atomic physics' in college. Of course, I had to do the E&M to get a degree in physics at some point, but I was not as good at it as I was differential equations. I found it tedious and boring. Today, I have a lot of textbooks on E&M, but they don't give me deeper understanding of electron flow.
Now let us list the 'condemned' physicists on this subject.
First: Jack Bybee, only an MA from UCB. Then classified projects.
Second: Dr. Vandenhul, once doing basic research but decided to study wire behavior, principally electron flow in wires, and made a successful business from it.
Third: Dr Hawksford, who DARED to do an article on wire problems that was not vetted by a referee.
Of course, and finally, Dr Otala, who also talked to me about wires and connectors in a meaningful way.
I hardly count in the general criticism. '-) (lousy BA in Physics)
I still use his quantum devices in my audio system, but I can't afford his new stuff. Jack Bybee taught me MORE about atomic physics than I ever learned in college. However, I also did not study 'atomic physics' in college. Of course, I had to do the E&M to get a degree in physics at some point, but I was not as good at it as I was differential equations. I found it tedious and boring. Today, I have a lot of textbooks on E&M, but they don't give me deeper understanding of electron flow.
Now let us list the 'condemned' physicists on this subject.
First: Jack Bybee, only an MA from UCB. Then classified projects.
Second: Dr. Vandenhul, once doing basic research but decided to study wire behavior, principally electron flow in wires, and made a successful business from it.
Third: Dr Hawksford, who DARED to do an article on wire problems that was not vetted by a referee.
Of course, and finally, Dr Otala, who also talked to me about wires and connectors in a meaningful way.
I hardly count in the general criticism. '-) (lousy BA in Physics)
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I haven't begun to list the E&M books in my possession. Just theory of metals looking for electron flow, especially at low voltage and current levels. I just want to know, as precisely as possible, how current really flows in a wire.
Another good reference is: ELECTRONIC CONTACTS HANDBOOK, Holm
I already have the Feynman series along with many other of his books.
Another good reference is: ELECTRONIC CONTACTS HANDBOOK, Holm
I already have the Feynman series along with many other of his books.
I'd guess that it actually was, which is why he couldn't publish it in anything other than popular fashion hifi magazines. If you crack open a few of those books you talk about, you'll be able to spot his elementary errors as well.
I've posted links repeatedly to a debunking of Hawksford's wire article; did you ever bother to read it, and if so, why do you disagree with the analysis?
Not that way.
Better get back to the basics, or more advanced treatments will be badly misunderstood.
Would be pretty hard to set that one up ...
One cute "trick": my wife's daughter, trained many years on the piano, rings up and a number of times has said, who's playing your piano, in the other room? Of course, only dealing with low grade phone link, but the reproduction is triggering the right acoustic clues from reflections in that room to convey the sense of a real instrument being played ...
Try it even with any solo instrument, with professional musician, and see if the musician will be fooled. It isn't likely that the musician will be fooled, however we wouldn't know before you'll try it.
Sorry, John, I wasn't actually referring to you as I know you have a science background - even though at times you seem to have forgotten some of it. I meant those who have never picked up an EM textbook.john curl said:
Here is the back-of-envelope calculation I requested:
Assume an interconnect with a capacitance of 100pF.
Assume nothing of any audio interest happens above 50kHz.
Then the capacitive reactance is 31.8k.
The cable will have a dielectric which may be non-linear or have other strange effects, but the source impedance for these strange things will be 31.8k.
Now assume that the effect, whatever it is, acts at the 1% level on the dielectric (anything this big would presumably already be known about). This means that the change in reactance corresponds to 3180k of added/subtracted impedance.
Now assume that the resultant signal distortion should be -80dB below signal.
This suggests a source impedance of 318R or above might show the effect.
This is an interesting figure as it is right on the boundary between typical SS vs. vacuum source impedances, and (perhaps) well-engineered (in the conventional sense) vs. ear-engineered (some so-called 'high-end') stuff.
Please note that this was a back-of-envelope calculation. Factors of 2 either way could appear at each step. I personally don't believe the 1% dielectric figure; I think reality is much smaller. However, it does demonstrate that cable issues may arise from using equipment which is inadequately engineered (in the conventional sense) by having too high source impedance.
Note that the calculation could be stood on its head, and used to show that if your source impedance is around 318R then you need a source impedance nonlinearity of less than 1% even with a perfect cable.
Don't. For plastic dielectrics, the figures are between 2 and 6 orders of magnitude lower.
Don't need reactance, constant C and input gm varying with tilt will do. Just take the real equation for voltage to current conversion at the input rather than just giving it a static value (gm) and run an expansion in the first two or three terms of it through the simple op-amp with feedback equation using A*sin(wt) as input.
This is all Barrie did, it's not rocket science. If you have Mathcad with the symbolic package you can do it directly by typing it in and say simplify, you don't even need to remember your trig identities.
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SY said:
I suspected as much. I think the utility of my calculation is that in broad terms it applies whatever the claimed physical effect is, provided simply that the IC acts as the C in an RC lowpass filter - and that is just the standard low frequency EM quasi-static approximation - and the effect worked by varying C.
Someone else can do the calc for triboelectricity - presumably he would have to estimate the likely charge dumped onto the cable.
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The problem is that if voodoo technical asserts can improve sells near naive customers, it devalues the credibility of their author near people with some scientific knowledge. Those last are often prescribers, and i believe the all story is not a good deal, on the long run.
I can understand that my marketing director could ask for names and colors of cables, like red for hot, blue for fluid, and green for natural, playing with the subconscious of customers, or invent fake arguments to sell at an expensive price his stock of good looking cables purchased with a big bargain.
As a designer, if I were asked about the subject, I would stay dead silent with a small smirk.
As a manager, for sure, i would ask my designers to design a cable based on transmission lines theory, and to provide the technical argues to help the selling of them. But i would certainly not allow people in the research department to spend time listening to their effects.
That is the whole story.
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Since you have not provided a schematic that's not a fair question. Those things you call "close" have plenty of possibilities. But please tell us why Ron thought it a bad idea, at best it falls below the residual putting it in with all the op-amps that do too.
Honestly, I suspect it wasn't. Any referee capable of examination at that level would have checked either the box [acceptable for publication after correction of specific errors]....or the box [not acceptable due to catastrophic errors]. I've had to check both boxes over the years, and I provided specifics as to why I did so.
edit: for the most part, the bulk of the errors I encountered were ones of test setup/design. Only on few occasions were the conceptual understandings flawed. The Essex Echo article contained both.
jn
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Segregation is applicable on studying and analyzing.
On setting targets and assigning resources (asking “what for?” and “up to where?”) that would be an irrational strategy.
Your very own engine/tires example, as well as any other conceivable one leased from aerospace technology to food cooking and beyond, proves this. I am sorry you torture your own mind.
In the world of audio, there was a case of a big and successful project, designed, studied, implemented and evaluated as a “system”. It turned to be the fetus of many long term studies and developments.
It has been documented through six sequentially chained symposium papers, linked below
http://www.alcatel-lucent.com/bstj/vol13-1934/articles/bstj13-2-239.pdf
http://www.alcatel-lucent.com/bstj/vol13-1934/articles/bstj13-2-245.pdf
http://www.alcatel-lucent.com/bstj/vol13-1934/articles/bstj13-2-259.pdf
http://www.alcatel-lucent.com/bstj/vol13-1934/articles/bstj13-2-278.pdf
http://www.alcatel-lucent.com/bstj/vol13-1934/articles/bstj13-2-285.pdf
http://www.alcatel-lucent.com/bstj/vol13-1934/articles/bstj13-2-301.pdf
Many (I say all but a minor one) of the issues discussed on each of them is still an alive and hot topic even today as if not a year has passed (what a surprise!)
Mr. Curl, calling contribution on technical issues (jneutron ) as non fitting to “REAL WORLD” of audio but wellcoming discussion on break-in and warm-up as they themselves are “serious issues for real audio designers” is well beyond my understanding.
Where does your reality stops and where the entertainment business begin?
George
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