What's the real scoop on cable "signal direction"

[kexodusc]

I've always wondered this, if you actually read the cable instructions or read the small print on the cables themselves, you'll often find an arrow or instructions telling you to run the signal path (ie from CD player to pre-amp or receiver) in a certain direction.
What's the real deal with this, does it really make a difference which end of a cable you plug into the source? If so why? What happens if you run it in reverse? Or is this just yet another goofy marketing ploy?
Thanks.

P.S. No flame wars, please

[mtrycraft]

I've always wondered this, if you actually read the cable instructions or read the small print on the cables themselves, you'll often find an arrow or instructions telling you to run the signal path (ie from CD player to pre-amp or receiver) in a certain direction.
What's the real deal with this, does it really make a difference which end of a cable you plug into the source? If so why? What happens if you run it in reverse? Or is this just yet another goofy marketing ploy?
Thanks.
P.S. No flame wars, please

Those cables may have a shield grounded only at one end. That is why the supposed arrow. Other than this, the signal is alternating, non directional.

[Demetrio]

Those cables may have a shield grounded only at one end. That is why the supposed arrow. Other than this, the signal is alternating, non directional.

So please clarify, what's the end of the cable that should be shield grounded? Or is that irrelevant?

Demetrio.

[mtrycraft]

So please clarify, what's the end of the cable that should be shield grounded? Or is that irrelevant?

Demetrio.

It is preferred to hook it up as stated, the arrow pointing in the direction of where the signal is sent to but audibility is not a real issue, just a preferred practice.

[DMK]

It is preferred to hook it up as stated, the arrow pointing in the direction of where the signal is sent to but audibility is not a real issue, just a preferred practice.

You mean the signal doesn't follow the arrows? I guess that would give new meaning to the "sound" of a CD player, no? Just try not to let the drawer hit you in the ear!

[Thomas_A]

As Mtry indicates, signal direction is not an issue since it is AC. Source direction (e.g. CD to amp) is also not important. What can be important in certain instances (more so if many components like CD, pre-/power amp, turntable, HT amp, TV, video, projector, computer etc) is that components are grounded properly to each other so that hum/ground loops are minimized.

A "semibalanced" cable have its shield connected to one end. So if there is a component acting as the star ground (usually the preamp or the integrated amp) the shield of the cable should be connected to this component. That implies that all cables are connected the same way, irrespectively if it is an in or output (e.g. pre out/main in, tape loop). In some pro equipment this can be crucial, depending on the internal ground looks like in the components.

Correct me if I am wrong.

T

[turbodog]

General agreement with the others. The advantage (if any) to grounding cables at one end is:
Many things can cause the chassis grounds in your various pieces of equipment to not be exactly the same. Even if they're plugged into the same outlet. When this happens, and if you connect these items with cable grounded at both ends, a 60-Hz current will flow in that shielding (except in countries running 50 Hz, of course). This 60 Hz current flow, in close proximity to the line level audio signals, will couple 60 Hz hum into the audio.

Thus, by grounding the cable only at the amp, you retain the shielding needed, but avoid the audio hum. You may want to connect a ground wire between the chassis of the various pieces of equipment, but do it away from the low-level audio signals.

The arrow is a reference to help you have all the cables grounded to the same place (the amp, if you so choose).