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Thread: Cable science

  1. #1
    Join Date: Jan 2013

    Location: Birmingham

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    I'm James.

    Default Cable science

    Thought I would post this up as it seemed appropriate as I am road testing the Spotfire IC from Oliver ( Bigman) at this very moment.

    https://www.stereophile.com/content/...agnetic-cables

  2. #2
    Join Date: Apr 2009

    Location: Melbourne

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    I'm Alex.

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    Unfortunately, I believe the company is no longer in existence. The part about simple nickel plated RCA plugs is interesting, as some cable designers are doing just that...Shindo for instance use Switchcraft RCA for their IC. IMO the Switchcrafts are very good, I use them currently as they were really inexpensive compared to WBT or Audioquest plugs.

    Likewise, in another thread, Belling Lee bananas, BFA or Pomonas are preferred over expensive banana plugs

  3. #3
    Join Date: Oct 2012

    Location: The Black Country

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    I'm Alan.

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    I've never read such tosh in all my life. Here appears to be the premise for the development of the cable:

    '...is that if the wire is thin enough—less than several skin depths—some of the signal can sink entirely through the center of the wire and come out the other side.'

    What? Sink through and come out the others side?

    To my knowledge the skin effect is due to opposing eddy currents induced by the changing magnetic field. Is this magnetic field somehow not present on one side of the cable?

    In the spirit of open-mindedness I invite anyone to explain how this works.

    Other tosh from later in the article:
    'Because the audio signal propagates outside the conductor, by necessity it must propagate through the cable insulation.'

    Propagation through insulation? INSULATION Utter crap.

  4. #4
    Join Date: Nov 2008

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    I'm AMusicFanNotAnAudiophile.

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    Quote Originally Posted by Firebottle View Post
    I've never read such tosh in all my life
    I didn't get that far - I saw where the link led, sighed, and shut the page down.
    Chris



    Once we've made sense of our world, we wanna go fuck up everybody else's because his or her truth doesn't match mine. But this is the problem. Truth is individual calculation. Which means because we all have different perspectives, there isn't one singular truth, is there?

  5. #5
    Join Date: Nov 2015

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    I'm Oliver.

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    It's interesting in a kind of "I don't believe what science says" way.
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  6. #6
    Join Date: Aug 2010

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    I'm Hugh.

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    Quote Originally Posted by Firebottle View Post
    I've never read such tosh in all my life.

    Likewise. Cutting edge bollocks of the very highest order.

  7. #7
    Join Date: Sep 2017

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    I'm Pavel.

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    Quote Originally Posted by Firebottle View Post
    Other tosh from later in the article:
    'Because the audio signal propagates outside the conductor, by necessity it must propagate through the cable insulation.'

    Propagation through insulation? INSULATION Utter crap.
    I think the guy is confusing propagation of electromagnetic field, which is indeed located outside the wires, with actual movement of charged particles

  8. #8
    Join Date: Apr 2012

    Location: Southall, West London

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    I'm Geoff.

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    Quote Originally Posted by Shovel_Knight View Post
    I think the guy is confusing propagation of electromagnetic field, which is indeed located outside the wires, with actual movement of charged particles
    I also suspect that may be so.

  9. #9
    Join Date: Aug 2010

    Location: East Midlands

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    I'm Hugh.

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    Quote Originally Posted by maxrob200 View Post
    Unfortunately, I believe the company is no longer in existence.

    "First Published: Feb 1, 1991" No wonder.

  10. #10
    Join Date: Jan 2009

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    I'm openingabottleofwine.

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    Despite the author having worked as a physicist at Los Alamos, he has a lop-side understanding of current flow in a conductor. In a conductor of circular cross section, the current density will, because of the skin effect for alternating currents, decrease towards the centre axis of the conductor, but because the geometry is symmetrical, the current will certainly not propagate across the diameter "and come out the other side".

    The author cites an example of 1mm diameter copper wire. If he had done the sums he would have found for a high frequency audio signal of 10kHz, the current density at the centre is 96.9% of the value at the surface. And at 10kHz the skin depth in copper is 0.66mm, so the 1mm diameter wire has a radius that is 75% of the skin depth, and thus is electrically 'narrow'; exactly the situation needed - the phase lag for current within the conductor is small. In attempting to reduce the skin depth by introducing magnetic material having a permeability very much greater than one, the phase lag of the current within the wire will be increased.

    The author also confuses the velocity of the current-carrying electrons with that of the signal propagation velocity! And claims silk is a better insulator as it has a lower permittivity than most polmymers. It has a permittivity of 2.5 -3.5; comparable to most other polymers (PTFE for example has a value of 2.1). Cotton though does have a low permittivity of 1.3 -1.4, so it could be argued that it might make a better insulator for cables.
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