If only it were that simple. The "skin/proximity effect" for supers does interesting things to the inductive storage mechanism. The superconductor wire/cable geometry, where the return conductor is, and the critical current of the super all come into play. Also, I rarely work with naked superconductors, but rather, ones clad with copper (niobium tin and niobium titanium), or YBCO, which is a film deposited and reacted on hastalloy (for strength), silver (early ones), or stainless with copper plating. At high slews (audio frequencies), the current will tend to run crowd at the edges of the super, and if too fast, will climb into the copper causing dissipation and quench. Of course, that's only my work experience...
Perhaps. What is more important here, is I've explained to you multiple times that the simple RF based t-line analysis provides a lag in current at the load, and that the inclusion of R and G SLOWS it down even more.
Stating that a simple analysis needs to be tossed because it doesn't "apply to audio" is a diversionary tactic ignoring the fact that the reality is even slower..
jn
What's more important is how to ***** the ridiculous claims being bandied about with respect to t-lines. Both from the crackpot viewpoint espoused without a whit of understanding, as well as blanket assertions on an audio website.
edit: interesting, a word which describes "the use of intelligence to figure out" was censured. I don't think it was a bad word, so was suprised to see astericks..
T line terminating zobels may indeed be useful if the amp has a high open loop bandwidth and the tweeter unloads before that breakpoint.
And if the load has excessive impedance variations in the audio band, using a high z cable can indeed introduce time delays that approach human ITD capabilities.
The bottom line is always, is it audible via real controlled testing.
For cable lifters and stands, the topic of this thread..My opinion is that they are bogus.
jn
edit: interesting, a word which describes "the use of intelligence to figure out" was censured. I don't think it was a bad word, so was suprised to see astericks..
T line terminating zobels may indeed be useful if the amp has a high open loop bandwidth and the tweeter unloads before that breakpoint.
And if the load has excessive impedance variations in the audio band, using a high z cable can indeed introduce time delays that approach human ITD capabilities.
The bottom line is always, is it audible via real controlled testing.
For cable lifters and stands, the topic of this thread..My opinion is that they are bogus.
jn
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With two cylindrical conductors, that is correct.
Within that model, the only avenues open for reducing the impedance is to reduce the insulation thickness, or increase the permittivity of the insulation, epsilon. Foamed dielectric will be about 1.05 to 1.5, and typical plastics run about 3 to 4. If you went mineral, like SiO2, you could get higher epsilons and therefore lower overall impedance, but that's not very workable and typically reserved for class 1E cables requiring 10 power 8 Gray radiation resistance.
But that's only for two parallel wires. If you take a cat5e cable for example, the 4 twisted pairs do not communicate with each other magnetically, so paralleling all 4 will give 1/4 the impedance. Double coax, such as a triax cable made with a core and two shields, will also have lower impedance shield to shield than the parallel model predicts. I've made cables with 8 ohms and 4 ohms impedance (rf model consistent with the link you provided) using double braid, copper foils, as well as many paralleled cat5e. And tested them all btw.
Given what I've read from friends here whom I have high regard for, I would not take stock in a review from that entity.
edit: that is not to say that a zobel is ineffective. It can be an essential element if the amplifier has a high unity gain bandwidth, the cables are very low impedance, and the load impedance gets very high at the frequencies where the amplifier still has open loop gain. In that case, the cable's capacitance will be the dominant, and the resultant phase shift can make the amplifier unstable. But I believe most current design amplifiers avoid that.
ps. Of note is that when conductor spacing (center to center) is set to zero, the linked model goes to minus infinity. It should go to zero.
And, when D is set to 2 and S set to 1, inductance is zero. That is incorrect.
But other than those conditions, it seems ok. For example, when S equals D, the inductance and impedance remain constant. Good..
jn
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So (speaking hypothetically and rhetorically here), if a cable has a characteristic impedance of 50 ohms, I should be able to put a 50 ohm resistor in series with it, connect this series connection to an audio amplifier, and it should see an impedance of 100 ohms through the frequencies of 20Hz to 20kHz, right?
Right, system7?
Right, system7?
Nah, it's basically an open circuit for the amp at audio, a 50 ohm resistor in series with a few feet of cable capacitance.
Ah, your descriptor wasn't good enough for me. The normal question is with the resistor at the far end connecting send and return conductors.
Next time, be clearer or draw a diagram. I'm just a country doctor..
jn
So basically speaking, it's all down to those Protons, Neutrons & Electrons, ain't it?
https://www.youtube.com/watch?v=N2wcr4OAsyo
https://www.youtube.com/watch?v=N2wcr4OAsyo
I hope not.
Don't you get it? The time to have an open mind about the physics of cables was over a century ago. Now we've moved on to keeping an open mind about some aspects of cosmology and the Standard Model of particle physics.
jeeze - just incorporate a thin sheathing of cavorite, and the cables will float themselves
next problem?
oh, you want to work in the real universe? that'll take a bit more work
next problem?
oh, you want to work in the real universe? that'll take a bit more work
Agreed on the date. So much was learned a while ago by the theorists.
Unfortunately, in the intervening time, much has been lost, ignored, or simplified to the degree that actual understanding and application to the real world has suffered. And, it allows pseudoscience a back door.
I learned about this stuff back in '74, and am still shocked by what many profess as correct. So much so, that I don't even bother informing web site owners of their inaccuracies. They won't listen anyway..
The people involved in that stuff are just so um, shall we say, "interesting"? Really nice guys and fun to talk with, especially at happy hour... but man, pretty eccentric..
Now waittaminute.. Real universe?? When did that become a criteria?? Did I miss a memo or sumptin??
jn
Just in case anyone is holding their breath (or ordering popcorn) I have no intention of reviving my fruitless discussion with jn on this matter. Interested people can use the search function.jneutron said:
Come on it was fun. 😀 After all there is only one answer it's not like there are two distinct different ways of expressing the storage of magnetic and electric energy in two wires twisted together.
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