How are cables directional?

On the contrary I find ABX testing near useless. You focus on the wrong things. You either hear an imnediate difference but can’t evaluate if it is overall better, or you focus on what you expect to hear, find it’s not there and conclude there is no difference (which there may in fact be none; let’s be honest).

For the really esoteric changes, it’s generally better to make the change; live with it for one to two weeks; then switch back and ask yourself whether you feel you gained something or lost something.

I am skeptical of any description that uses phrases like “it was like night and day”.

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My radio training in the RAAF informed me that skin effect was not a problem until one reached 2MHz and above, then Litz wire was required for Valve radio circuits (showing my age here).

This a question of sorts for the brain trusts out there. Would there be a difference if we compared Class A amplification to push-pull Class AB? Where Class AB, the AC signal swings above and below zero ground volts. Could therefore Class A be directional if there is no DC blocking capacitors used in the circuit, thus the possible requirement for directional interconnects.

I have never seen a NAIM circuit diagram of any sort. This is just a query from a tech point of view, not a radio engineer’s point of view. My escape clause. I can vouch that I have heard differences in speaker cables and having the grills off the speakers when playing music. Yes, I do also have directional Naim interconnects plus others from wire-wound, I think.

Mitch in Oz, reading on.

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When electrons travel down a wire in one direction they generate a magnetic field around the wire. From memory, and please check my year 12 physics lessons it is the right-hand grip rule. Your thumb points in the direction of flow of the electrons and your fingers curl around the conductor in the direction of the magnetic field that is generated.

I hope this helps.

Mitch in Oz.

I see that JimDog also enjoys a nice Australian red. The bottle is directional as the glass fills up. The glass is directional as it empties, though it does not go back into the bottle. Case proved, direction matters :smile:

Mitch in Oz.

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Another case of directional investigation.

Mitch in Oz.

If they aren’t playing at the same time you presumably always have to remember.

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Almost right - if you’re using your right hand, the thumb points in the direction of conventional current (positive to negative, i.e. the opposite to the electron flow).

If you want the thumb to represent electron flow, you can just use your left hand instead!

Mark

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G’day @Ebor , you are quite correct. I did not wish to confuse things with members having to understand the difference between the two.

Warm regards,

Mitch in Oz.

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Lenz’s Law. But more importantly, it’s called the theory of electromagnetism for a reason. You can’t have one without the other.

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image

Does Ampère’s right-hand grip rule apply equally to AC and DC circuits?

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No… :expressionless:

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It applies to any moving charged particle, whether it’s in a wire or circulating in the LHC close to the speed to light!

Fundamentally, it shows us that charges can’t move through space without creating a magnetic field as a result, a bit like a duck or ship can’t move through water without causing ripples.

Mark

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It’s clear how that applies to a direct current coming from, say, a solar panel.

How would it work in a UK mains AC circuit?

You would need to change hands 50 times per second…

The magnetic field reverses 100 times a second (a complete cycle 50 times a second), so as a consequence when wrapped around a ferromagnetic object it will tend to demagnetise it, as opposed to creating an electromagnet, potentially with lasting magnetism depending on the material.

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Simplistic answer: as the current (constantly) changes direction, the magnetic field also (constantly) reverses direction.

Slightly less simplistic answer: since the electrons are constantly changing velocity ( = accelerating), they will radiate electromagnetic waves. Fundamentally, this is how radio transmission antennas and many other EM wave transmitters (eg. TV, mobile phones, WiFi hubs) work. It’s a bit like bobbing a cork up and down on water to make ripples.

@Innocent_Bystander’s reference to demagnetising a ferrous core isn’t quite how I’d put it. Something similar used to be used to blank recording tape, but only by exposing the tape to a strong varying magnetic field and then slowly removing the tape from the field. In a transformer core, the AC in the primary coil constantly and repeatedly magnetises and demagnetises the core, which then induces an AC in the secondary coil. The ability of any type of Iron to respond quickly to this constant cycling and not retain any permanent magnetism is what makes it good (or not) for use as a transformer core material.

Mark

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Only thing I’m thinking of is how many times one could have changed direction of the cable and have a listen between post 1 and 157.

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According to this video, electrons move slower than a snail.

And a lot slower than electricity.

The video has the electron drifting towards the black end of the battery - which is normally the positive terminal of an Energizer battery.

Is that correct?

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Electrons are negatively charged, so will move towards the positive charge.

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Yes, of course.

A similar description is given by Nick Lucid in this video but with much fine detail:

He says that electrons move at 4cm per hour in a copper cable.

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