directional cables

i was talking to a buddy of mine about directional cables and i was wondering if any of you guys had a link that talked about them and the difference b/n a "directional" cable and a normal one. or if any of you are positive about this topic, your insight could help as well. thanks

I think the difference between directional and non-directional cables is that one has arrows printed on its jacket and the other ... sounds the same.

Jeff Mackwood

Other than possible shielding concerns which isn't REALLY directional, but which makes the arrows useful, it's crap.

If the shield is only attached at one end, a good practice generally speaking, then there might be a preference as to which unit got the drain wire.

I've always had the impression that the concept of "direction" in cables has it's roots in solid engineering principles. That principle being an overall shield connected to the ground terminal at only one end of the cable. There are a couple different schools of thought on where the grounded terminal should be connected, at the signal source (where the signal is weakest), closest to earth ground, or whatever sounds best. Anyway, I think what has happened is that when the cable manufacturers started putting arrows on the cables (to indicate which end the shield was connected to) it just added fuel to the whole debate about cable manufacturers being Voodoo vendors. I mean think about it, that a signal would "flow" better in one direction than another just sounds absurd. But knowing what I just said about the shield being grounded at only one end it kinda makes sense doesn't it.

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Tekdredger

It's done because the outer shield is only connected at one end. Which end this goes to is up to the opinion of the manufacturer.

I think where it gets confused is sales and marketing. The principles are well known and practice long ago perfected, like most other things in this realm. But marketing can be almost limitlessly clueless and at the same time almost limitlessly creative - not a great combination.

ok that was our consensus too.

I am a little confused now. While I understood that the cables with arrows on them typically only had shielding connected on one side, I thought the arrow pointed in the direction of the desired signal flow.

This implied that the grounding should occur at the side of the cable the signal originated at. Am I misundertanding this or have I just bought into the snake oil?

And if you buy into the theory that the grounded end must be at the (origin / destination - choose one), then I suppose that you will end up with some cables with jackets connceting to a particular component and some not - in the case of components that both "send" and "receive" a signal (receivers / pre-amps, recording devices of all types etc.) Now tell me that I'm going to hear a difference. And if I do, why not just swap the cables around until it sounds better. So what was the real purpose behind the arrows? Seems like leaving them off gives me an equal chance of plugging them in in a manner that yields the best sound - again assuming that it does make a difference. Which is why I said that they "sound the same".

Jeff Mackwood

Is this about audio and video cables? For audio, are you referencing both balanced and unbalanced connections? For unbalanced connections, are you thinking of a single conductor inside a shield or twisted pair inside a shield, the shield common with one of the inner conductors only at one end? Directional cables may be a new concept for people and this additional information may aid in understanding.

I can't answer for anybody else, but I was refering to audio interconnect cables. My presumption (note I am not 100% positive)was that they contained a twisted pair representing the positive and negative flow and also had a shield that was only connected to the ground side of the originating cable.

I admit that I was making an assumptions that the direction arrows were meaningful from an electrical engineering perspective (which is something I know little or nothing about). I am not suggesting that people shouldn't experiment and go with what sounds best to them. I was more interested in knowing if there really was a measurable difference in the level of shielding provided. If there isn't then I will concede this is snake oil.

Unbalanced cables that use the arrows have twisted pair cable inside for the "ground" and "hot" leads. Connecting the shield at one end only ensures that crud that is blocked by the shield is not transmitted component-to-component. Balanced (professional) cables generally have the shield connected at both ends since many cables may be connected together in a pro environment and there is no time to waste trying to figure out if this cable or that cable has it's shield connected at only one end. The shield tab isolation is taken care of at the equpment end.

the question was in re: to unbalanced ics, and what most people said is what we thought as well. thanks. oh and sh, i thought you said you were not going to respond to my topics. lol, j/k.

Sorry, I'll check to see who started the thread next time.

Soundhound: Thank you for confirming my understanding of the construction. I would like to reconfirm that I understood one aspect of you previous comment correctly.

By stating that "Connecting the shield at one end only ensures that crud that is blocked by the shield is not transmitted component-to-component." imply that there is some merit to the validity of the direction arrows?

It has a lot to do with eliminating noise from ground loops.

Conecting the shield at one end only is a valid concept. I just think that the manufacturers are making it seem more than it really is. If they would just say what it is really for, isolating components, then the arrows would make more sense. Implying that cables are inherently "directional" to electron flow is just lying.

Charlie, yes, ground loops too. This connection behaves differently in balanced and unbalanced circuits - ground loops are still possible in unbalanced circuits since the ground must sill be connected between components.

I worked many years as a Transmission Engineer with a very large Telco. We always terminated the shield at the transmit end. In audio equipment that would mean the Out Jacks.

Yep - I designed and supervised installation and startup of industrial control systems, probably the worst place for EMI I'll ever see. And as 'hound pointed out, in typical RCA stuff for AV the outer conductor is also a potential ground loop carrier.