How essential is shielding?

What do you guys mean by "dead quiet"?

Niacin - I mean (1) With the system turned on and no music playing, with the preamp volume in the maximum position I ever make use of, no noise is audible at the listening position; and (2) With the system playing music at my average listening volumes, with a good recording, during moments of silence between passages, the system sounds indistinguishable from being off.

4est and Elizabeth - You make a good point about shielding being more important in some environments than others. I've just been wondering if those environments are not as ubiquitous as manufacturers of exclusively shielded cables would lead us to believe, which brings me to...

Lokie - That Cardas video was exactly one of the examples I had in mind of a manufacturer advocating the exclusive use of shielded designs.

Al - Thanks for your excellent input. I looked at the linked paper, and I have a stupid question. Here's a passage from the paper:

To eliminate hum, we must effectively eliminate interchassis ground current. We could eliminate it by simply breaking the chassis to chassis shield connection. Of course, this alone would not solve our problem.

Here's the stupid question: Why? What would happen if you "simply [broke] the chassis to chassis shield connection" in an effort to eliminate interchassis ground current?

Thanks,
Bryon

Here's the stupid question: ... What would happen if you "simply [broke] the chassis to chassis shield connection" in an effort to eliminate interchassis ground current?

Hi Bryon,

That isn't a stupid question. The answer is that you would also be breaking the signal return path. Keep in mind that electricity only flows if there is a complete circuit, from source to destination and back.

If you were to break that return path in the interconnect cable, and both components had 3-prong power plugs, the return path that would be taken would be through the ac safety ground wiring of the power cords, and whatever additional safety ground wiring would be necessary to reach a ground point that is common to both components. That would result in noise problems.

If either or both of the components had a 2-prong power plug, and no other ground path existed in the system between the components, then the destination component would see a "floating" input voltage (i.e., one that is not referenced to its own ground). That would result in uncontrolled behavior, and very conceivably in full-power noise levels that could damage the speakers.

Best regards,
-- Al

The answer is that you would also be breaking the signal return path.

I thought so, but it was unclear to me what the audible results would be, which the rest of your answer describes very nicely. Thanks, Al.

While the hazards of using unshielded interconnects make sense to me (particularly when they are unbalanced), my experience has been that I like the sound of unshielded interconnects. I'm currently using unshielded interconnects from Morrow, but I have also used ones from Kimber and Anticables. Like other listeners, I have experienced an "openness" with unshielded designs that is appealing to me. I'm not saying you can't get that with shielded designs, but I haven't had much luck finding it, except for a $2k+ pair of Synergistic cables that I owned for a while.

I'm not suggesting that unshielded cables sound inherently better than shielded ones. Just that I've had a easier time finding the sound I was looking for with unshielded designs, at least among more affordable cables. This could, of course, be an artifact of a small sample size.

And, FWIW, I have also experienced a similar improvement in "openness" going from a heavily shielded PC to a lightly shielded PC on my preamp, as reported by Lokie.

Bryon

Devil's advocate: Given that a system is dead quiet with unshielded cables, how are any of you comparing shielded and unshielded cables, and know that the 'openness' that was mentioned (or any other sonic difference) is due specifically to an absence of shielding? One would need 2 identical cables, the only difference being shielded vs non, in order to make a reasonable comparison.

Tholt: Your point is valid and in my case, I made the assumption that it was the shielding, but I could be wrong.

I had a conversation about power cords with Chris Hoff at BPT and his theory is that if you don't have any high register nasties or buzzing then shielding is a form of filtering and detrimental to the sonics. His power cord comes with or without shielding, so this would be a good cord to experiment as Tholt's "reasonable comparison" theory suggests.