Cable directionality

[kasperhauser]

I've got a sure-fire solution to the whole problem and I'm willing to publish it at no charge just to help mankind considering the difficulty and importance of the matter:

Connect them observing recommended directionality as provided by the manufacturer (little arrows silkscreened on the insulation point in the direction of signal flow) and forget about it. Alternatively, connect some or all of them the wrong way 'round and pat yourself on the back that you're a Savvy Audiophile, pulled one over on The Man, or just generally smarter than all who do not do as You do.

If you don't like my advice, no problem. You got what you paid for.

My approach is even easier. I just connect them, without even spending a tenth of a nanosecond looking for or caring about little silkscreened arrows or giving the slightest thought about what the manufacturer may or may not know. I also leave off the self back patting. This approach has never failed yet, and think of all the tens of nanoseconds I've saved. No fretting, no worry, and I'm on with my life ever so slightly before you.

 

[russel]

The OP Sue asks some interesting questions and is obviously intelligent however there are very few scientists or at least that make themselves known on pfm.

I guess Sue didn't take 'O' Level Chemistry or if she did it wasn't well taught.

There are different types of chemical structure but metals have what is called metallic bonding. You'll never guess why! In the metallic bond 'free' electrons distribute themselves as a 'sea' of free electrons rather like a fluid travelling over the atoms. Thus the small amount of impurities have practically no effect on this pool of electrons but rather alter the Xtalline structure of the metal with various results. Thus there is no directional effect the sea is free to move under electrical and magnet influence i.e. the electromagnetic force. Simple cables carrying analogue signals can however be directional but that is to down with earthing arrangements.

When we get down to the Quantum level you'll find that the electron tends to 'smear' itself out. Take a simple Hydrogen atom with one electron orbiting a single proton. Calculations from Schrödinger's wave equation result in an electron 'cloud' distributed within the 's' shell. The cloud represents the probability of the electron being at that point. Think of a bicycle wheel. At rest you can see the spokes and can easily poke a straw between the gap in the spokes. Now spin the wheel fast and the spokes begin to look like a cloud. Can you now poke a straw through the gaps? There is a probability that you can if you are fast enough!

In the case of Hydrogen the electron in the s shell forms a sphere but other electrons in the p shell follow a dumbbell shape and those in the d shell a petal shape and so on not to mention things like sp3 hybridisation that gives rise to the very strong covalent bond between Carbon atoms. Think diamond the hardest element in the Universe and just pure Carbon if it is white.

The gist of the above is that electrons are not hard solid bits of stuff like a dry pea rather that they tend to smear out over quite large distances and have probabilities of being anywhere hence things like the Tunnelling effect which is like you placing a ball on one side of a wall and it will appear on the other side. Have you heard of Tunnel Diodes?

Sleep well.

DV

If cables were directional the effect would have been noticed in early telephone systems where speech was transmitted over hundreds of kilometers. I have heard of tunnel diodes and they are made of heavily doped semiconductors, not metal and yes I do sleep well.

 

[Sue Pertwee-Tyr]

Super Tweeter, they're saying its highly unlikely, not remotely that it is possible, except for the example Robert gives.

Yes, it was Robert's example which I had in mind when I referred to one specific example. I realise the grain boundary thing is considerably less likely, but another bit of half-remembered metallurgy from my uni days did seem to suggest that grain boundaries can have some sort of diodic effect, albeit low level and certainly not enough to do any meaningful rectification.

My main point, as it was in the Bedini thread, being that, sometimes, a little thought can suggest a possible mechanism by which something can happen. It is then not a question of dismissing it out of hand, but rather of discussing whether the effect would be measurable or audible.

Darth, you clearly have the advantage over me, your 'O' level may have been 15 years before mine, but you used your chemistry afterwards in your career. Mine stopped after 'A' levels in 1978, apart from some fairly basic metallurgy in my first year at uni. I'm afraid much of that knowledge has made room for other things.

 

[hammeredklavier]

If any aspect of a conductor's electrical properties meant that current could travel through it more easily in one direction than another, then my guess would be that it would be a VERY poor choice for alternating currents, since it's sure as hell going to have to carry those electrons against the grain 50 % of the time whichever way round you connect your cable.

 

[Sue Pertwee-Tyr]

If any aspect of a conductor's electrical properties meant that current could travel through it more easily in one direction than another, then my guess would be that it would be a VERY poor choice for alternating currents, since it's sure as hell going to have to carry those electrons against the grain 50 % of the time whichever way round you connect your cable.

Well, perhaps. But finding a cable which didn't have grain boundaries introduced by the drawing process might be tricky. So 'they all do that, sir' means that you'd simply take the one which does it least.

It is not in dispute that conductivity of a metal varies with purity (ie presence and quantity of impurities), and the amount of grain boundaries. This, I think, is accepted physics.

 

[hammeredklavier]

Well, perhaps. But finding a cable which didn't have grain boundaries introduced by the drawing process might be tricky. So 'they all do that, sir' means that you'd simply take the one which does it least.

It is not in dispute that conductivity of a metal varies with purity (ie presence and quantity of impurities), and the amount of grain boundaries. This, I think, is accepted physics.

That maybe so, but the point I'm making is that the cable would be equally handicapped by this whichever way round you connected it. Unless it was carrying DC, in which case, the polarity would obviously make a difference.

 

[darrylfunk]

Well, perhaps. But finding a cable which didn't have grain boundaries introduced by the drawing process might be tricky. So 'they all do that, sir' means that you'd simply take the one which does it least.

It is not in dispute that conductivity of a metal varies with purity (ie presence and quantity of impurities), and the amount of grain boundaries. This, I think, is accepted physics.

so why are ohno cast single crystal cables still directionally marked if the casting process is designed to remove any boundary?

 

[Pete MB&D]

Hi,

The late JV said cable wasn't directional until the insulation was applied.


Pete

 

[hammeredklavier]

Hi,

The late JV said cable wasn't directional until the insulation was applied.


Pete

I think he was close. I would say, the cable isn't directional until funny little arrows are painted on the insulator...

 

[Eyebroughty]

Hi,

A couple of questions.

As a non technical person can I ask this.

1) How do they know which is the "correct" direction to start with?

2) If interconnects and speaker cables are the subject in question where do power cables come in this area. Surely they all carry electricity in some shape or form?

Cheers

John

 

[hammeredklavier]

If interconnects and speaker cables are the subject in question where do power cables come in this area. Surely they all carry electricity in some shape or form?

Cheers

John

Power cables, like speaker cables and interconnects, carry alternating currents, which means that the electricity they carry is constantly changing direction. In mains electricity, this is a simple 50 Hz oscillation, so positive and negative effectively swap over 50 times per second. You don't need to be a whiz physicist to see why this makes a nonsense of cable directionality: the current they carry is constantly changing direction!

 

[Pete MB&D]

Hi, Hammeredklaver

That’s a theory, have you tested it?

Remember the sun was said to revolve around the earth, that was the theory.

Pete

 

[hammeredklavier]

Hi, Hammeredklaver

That’s a theory, have you tested it?

Eh? Alternating current means that the currents keeps changing direction - which distinguishes it from direct current (DC), where it doesn't. In AC, the electrons therefore move in both directions through the conductor...

 

[Pete MB&D]

And? what does that have to do with the way it sounds?

Have you tested it?

I can notice a slightly brighter sound one way with interconnect cables, and a difference between solid and stranded cables, because i have tested the theroy out.
Not said it can't happen, are afraid of falling off the end of the world ;-)

Pete

 

[hammeredklavier]

And? what does that have to do with the way it sounds?

It means that cables carrying audio signals cannot possibly have a direction, because the current they carry doesn't have one.

Have you tested it?

Do you mean, have I swapped a cable round and thought I heard a difference? Yes! I used to have an Avondale Grad One pre-amp, and tried reversing the cable connecting it to the PSU. It appeared (!) to sound different. But then, that cable carries DC, not AC... and even so, in retrospect, I am happy to accept that it might well have been my imagination. I've regularly swapped interconnects and speaker cables around and heard no difference whatsoever.

I can notice a slightly brighter sound one way with interconnect cables, and a difference between solid and stranded cables, because i have tested the theroy out.
Not said it can't happen, are afraid of falling off the end of the world ;-)

Pete

These things do sometimes seem to affect the sound...

 

[Pete MB&D]

And you Seem to hear music.

Pete

 

[hammeredklavier]

And you Seem to hear music.

Yeah, which is the most important thing. To be honest, I'm not as interested in hi-fi as I once was, certainly not in mucking around with cables and so on. I see both sides of the argument here. I remember when I was young being totally convinced cables made a difference. I remember replacing the bellwire on my mission 780s with QED 79 strand and being blown away by the difference. (Although I was expecting to hear one!) More recently, when I was agnostic about such things, I have had cause to replace cables for practical reasons rather than because I thought it'd improve anything, and since I needed to save money, these replacements tended to be cheap common-or-garden cables off the 'bay. In all these cases, there was either no difference, or if anything, the cheapo cable sounded better! I think some of these weird and wonderful interconnects especially are designed to do things to the signal rather than merely carry it.

 

[bob atherton]

Do you mean, have I swapped a cable round and thought I heard a difference? Yes! I used to have an Avondale Grad One pre-amp, and tried reversing the cable connecting it to the PSU. It appeared (!) to sound different. But then, that cable carries DC, not AC... and even so, in retrospect, I am happy to accept that it might well have been my imagination.

These things do sometimes seem to affect the sound...

I don't understand why some people have to beat themselves up a little if they hear, or think they hear, a difference in, cable directionality, cables, amplifier, mains cables etc etc.

Just because science says that there can't be any audible difference why do we not trust our brains and feelings?

It's like looking at the sky and thinking it's blue. Science will prove that it is not blue but I go with what I see, and hear.

(OK, the sky has not been blue over Bristol since March, but you know what I mean..!)

 

[Engels]

But there are good reasons why the sky looks blue... (and grey)

If a plain un-screened, un-terminated cable can be directional, how does the manufacturer ensure they get the wire the right way round before they put the insulation around it?

There may be a reason why the sound changes when you flip the cable other than expectation bias, but it is'nt because of simply swapping the copper conductor ends around

 

[Pete MB&D]

If a plain un-screened, un-terminated cable can be directional, how does the manufacturer ensure they get the wire the right way round before they put the insulation around it?

Hi,

The late JV said cable wasn't directional until the insulation was applied.


Pete