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Cable directionality

I'm sure this has been discussed before but I missed it, so what is all this stuff with the direction of voltage flow with cables? Every cable you see any more has a little arrow on it. Since the signal is AC and travels one direction as much as it travels the other, what difference could this possibly make. I have talked to numerous co-workers (all electrical engineers) and they ALL say this is the biggest bunch of bunk they have ever seen. Since I am the only "Audiophile", I try to keep an open mind(I'm also the odd man out being mechanical.) Skin effect, resistance, capacitance, etc. are true issues. You pass power through a wire and it creates a magnetic field. You do deal with impedence and synergy with the driving source. How about a few technical answers from the audiophile community.
bigtee
audioengr
3,282 posts
 
In general, the reason that the shield of a twinaxial cable is grounded at the source is because this is where the signal is being driven. The most accurate ground reference for a driver will be at the driver, not at the destination component. If there is noise developed across the signal return, then this will not be induced on the shield as it will if you ground the shield at the destination end. The felling is that the ground will be noisier with respect to the signal at the destination end compared to the source end.
marakanetz's avatar
marakanetz
5,473 posts
 
I'm glad to hear the vast word from Audioengr!

I might add that conductors inside the cables have a certain % of impurities that have mostly semi-conductive structure; there are some dielectrical micro-structures as well. All these components might play the role while the cables burn-in but not on directionality.

Orbeck, the metal does change but with larger signal levels when the electric break-in of impurities occurs. With line level signals this is nearly-impossible.
marakanetz's avatar
marakanetz
5,473 posts
 
And another cable question to Orbeck:

How long it's needed to take off the statics from the dielectric if it's all we need to break-in the cable?

I would estimate it to tenths fractions of the second or even less...
bigtee OP
803 posts
 
Geeze, Here we go with the signal return, etc. The signal returns on the same line it went down in the first place. It is AC, therefore, it alternates according to frequency. What has the ground got to do with the signal wire other than it helps isolate the signal from the effects of interference. That is like saying that the AC line in your house alternates on the ground wire. I have taken bare wire (wonderwire to be exact) and plug one end into a CD player and the other into the amp. You know what---it worked fine (other than the radio station I picked up a few times.)
rives
953 posts
 
I'm glad we have a cable designer here--welcome Orbeck. As a physicist I like hearing the scientific explainations, when I can only surmise the bits I know about cables. It's certainly refreshing to the hocus pocus.
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