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Old 10th August 2011, 08:24 PM   #511
jneutron is offline jneutron  United States
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Originally Posted by scott wurcer View Post
If properly soldered to end terminations, I see no possible way to sustain any potential between strands of multistrand wire.
Only by forcing skinning can it be done. As you say, properly soldered and DC, there is no way.

edit: skin effect is the result of Faraday's law of induction applied to the conductor, a consequence of changing the transport current of the conductor. It creates toroidal currents which enhance current density at the outer region of the conductor, and reduces the total currents at the core. The net effect is to force the transport current to the outer surface, or skin, of the conductor. Interstrand insulation prevents these toroidal currents. A corroded stranded wire will "attempt" to act like a litz.
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Originally Posted by scott wurcer View Post
JN's example of course is possible but I would like to see a detailed analysis of how much potential could arise due to this.
Um, I already stated it.

15 nH is the total internal inductance. And, that is the only thing.

The coax method is a method of reducing the rest of the inductance while keeping external noise out as well.

Jn

Last edited by jneutron; 10th August 2011 at 08:30 PM.
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Old 10th August 2011, 08:27 PM   #512
scott wurcer is offline scott wurcer  United States
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Originally Posted by jneutron View Post
Interstrand breakdown will produce even order harmonics.
Cheers, jn
??? If the rectifying system is Cu-CuxSy-Cu I don't see the assymetry. This experiment has no way to get at the "junk" layer by itself with an ohmic connection.
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Old 10th August 2011, 08:31 PM   #513
BudP is offline BudP  United States
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John, what does effective dielectric coefficient mean? A simple answer would be helpful, I only design audio transformers, so cable differences are beyond my pay grade.

Bud
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Old 10th August 2011, 08:33 PM   #514
Esperado is offline Esperado  France
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Originally Posted by jneutron View Post
I have used the term IID. This is Interaural Intensity Difference.
I have used the term ITD. This is Interaural Temporal Difference.
Both together are used by the human brain to discern the location of the source.
I'm passionated by music. (My mother was a pianist)

As a research and development engineer, in a hifi equipment company, i was passionated by all the technical aspects witch make this magic: Make believe to the presence of musical instruments and musiciens in your living room with such a garbage of carbon, Silicium, Coper, Magnets, partial technical knowledge, luck and other paper cones glued together with economical preocupations. Trying to minimize the luck factor and to increase the knowledge's one.
Part of our mission was to help marketing in producing technical arguments (curves, words and formulas) to convince the naive and gullible customer that our products where constructed by God itself. It was very funny to tell fairy tails with real measurements.

As a sound engineer both in music, concerts and movie industry, i was involved in producing realistic sonic landscapes with expensive garbage equipments in various bad acoustics environments.

As an old man, i've read and listened so many crazy things even from respected sound engineers ...
One day, if i have time, i will write a web page on my site to demonstrate how my supermarket electric wires are superior against all existing others.

If you glue that together, you will understand some of my reactions and positions.

As a french guy, my English is far from satisfy the hifi minimum requirements. (sorry if some misunderstandings or lacks of nuances from my side). But i had read your posts with much of interest, and read hundred pages about some technical questions you talked about since two days, i love to learn new domains and correlate them with my too little knowledge.

This localization and "sound in space" question is passionating me. I've read thousand of books and research white papers about this subject. Used very interesting and exotic studio's stuff to manipulate sound space durin mixing process.Worked a lot on loudspeakers horns filters and enclosures. In the time domain too.
I wonder this incredible and mysterious instrument witch is our ears witch capture pressure variations and our brain witch treat them when it comes to listen to sounds and music.
And the mystical way are build our senses ( logarithmic and differential) while we all think in such a linear and integrating way.
But that's if far out off topic ?

Last edited by Esperado; 10th August 2011 at 09:03 PM.
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Old 10th August 2011, 08:46 PM   #515
jneutron is offline jneutron  United States
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Originally Posted by scott wurcer View Post
??? If the rectifying system is Cu-CuxSy-Cu I don't see the assymetry. This experiment has no way to get at the "junk" layer by itself with an ohmic connection.
Find a picture which details the toroidal currents that flow when the transport current changes. Notice that the currents have to flow across strands. If there is no interstrand conductivity, there is no skin effect. Like litz.

The exclusion of current from the core of a conductor due to skin effect is magnitude (of rate of change) based. In other words, it happens in both directions of the current. Hence, it is 2 times frequency.

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John, what does effective dielectric coefficient mean? A simple answer would be helpful, I only design audio transformers, so cable differences are beyond my pay grade.

Bud
edit: for velocity V, it is fraction of light speed...sorry, forgot to mention that...

For a coaxial cable, the general case for prop velocity is V = 1/sqr(epsilon times mu). Since most dielectrics have a mu relative of 1, the equation becomes:

V = 1/sqr(epsilon) (edit..epsilon is the relative dielectric constant of the insulation)

This equation is accurate for any constrained transmission line, so is useful for cables made using flat conductors as well, as long as the dielectric is very thin in comparison to it's width.

Also used is : V = 1/sqr(LC). just be careful of units. (edit: this is actual velocity, not fraction of C)

For regular wire pairs, the magnetic field is not constrained like the coaxial case. So you cannot use the simple V = 1/sqr(epsilon). It is necessary to use either the LC equation, or the "effective dielectric constant".

For my needs, it is useful to use "effective dielectric constant" in place of "dielectric constant" when considering cables which are like zip cable. It is a hybrid entity which considers both the capacitive as well as inductive energy storage of the wire. And, it is accurate for velocity as well..

In all cases, the equation:

LC = 1034 EDC L in nh per foot, C in pf per foot.

describes the relationship between the inductance and capacitance of any wire pair.

If you take the measured values of L and C, and use the LC=1034 EDC equation, you can derive the EDC, and 1/sqr(EDC) gives the prop velocity.

Cheers, jn

Last edited by jneutron; 10th August 2011 at 08:59 PM.
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Old 10th August 2011, 09:08 PM   #516
DF96 is offline DF96  England
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Originally Posted by jneutron
Please ask questions of me instead of going off on tangents..
As I was replying to SY's comment on something MT said, why should I consult you? As it happens, I believe you and I are probably not too far apart on this particular topic, but so what? If I wish to "go off on a tangent" (in your opinion) then provided it is within the general topic of the conversation (speaker cables?) and the mods are happy then I am free to do so.

John, please don't jump to the conclusion that if one of my posts happens to immediately follow one of yours that I am replying to you. Time delays insert a degree of randomness. If I happen to say something which differs from you in some detail please don't assume I am arguing with you - in some cases I might not even have seen your post first. I might be arguing with someone who is much further away from my own opinion.
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Old 10th August 2011, 09:16 PM   #517
DF96 is offline DF96  England
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Originally Posted by jneutron
The exclusion of current from the core of a conductor due to skin effect is magnitude (of rate of change) based. In other words, it happens in both directions of the current. Hence, it is 2 times frequency.
Interesting point. I hadn't thought of that. Now you have pointed it out it seems obvious! However, won't a 2f change applied to a a signal result in a 3f distortion product?
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Old 10th August 2011, 09:26 PM   #518
Esperado is offline Esperado  France
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Interesting point. I hadn't thought of that. Now you have pointed it out it seems obvious! However, won't a 2f change applied to a a signal result in a 3f distortion product?
What ?
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Old 10th August 2011, 09:38 PM   #519
DF96 is offline DF96  England
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Originally Posted by Esperado
What ?
Let us suppose that the resistance of the cable varies at 2f. (I am not saying that it does, but let us assume that it does). This is equivalent to multiplying the signal f by 2f. The result will be f and 3f components.

Does the resistance vary? I am not sure it does. Skin effect depends on frequency, not amplitude. So maybe I was too hasty in post 517.
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Old 10th August 2011, 09:52 PM   #520
SY is offline SY  United States
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OTOH, we're worrying about relativistic corrections to a cricket ball.
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