cable dielectric cause of artificial sound

I agree with Tplavas.
The cable geometry makes more of a difference in sound than dielectric types (if we're just counting the big 3: Teflon/PTFE, Polyethylene, cotton). Air is the best dielectric but difficult to manufacture successfully because copper will oxidize over time when exposed to air.
Manufactures feel it necessary to use PTFE because it's considered among the best solid dielectric, they can't charge a high price for an inferior insulator such as PVC.
Geometry such as multiple conductor braids, litz, effect the sound drastically. In my experience, a cable with high inductance will yield a sound that is smoother/warmer.

Elizabeth,

Chris VenHaus of VH Audio sells a 28 gauge solid core silver wire that's insulated with four layers of cotton serve and has a very uniform outside diameter which would make it very good for twisted pairs or, my preference, braided quads.

It's $59.99 for a 25 foot spool.

se

I think people freak out too much about copper wire oxidizing. Unless it's oxidation between mechanical contacts, I haven't found it to be any problem at all. It's only a few molecules thick and I find that much more preferable to a whole hell of a lot more plastic extruded over the wire. Even the thinnest enameling is orders of magnitude thicker.

Some say copper oxide isn't very conductive. Yeah? So what? Teflon isn't very conductive either. Nor the air surrounding the wire. Essentially all the oxide is doing is effectively reducing the diameter of the wire by a few molecules, which is nothing compared to the variation of wire diameter due to manufacturing tolerances.

se

Agree, audiophiles are often too critical with minor details, but oxidation which occurs at the surface of a conductor must be taken seriously. Electrical signal tends to travel at the surface of a conductor, NOT the center of a conductor as some may think. One example is the conductor designed by Analysis Plus, they design a conductor which is hollow in the center. Allowing the surface of a conductor to oxidize over time will change the character of the cable and shorten cable life. Oxidation is a reason why air dielectric is not used more often.

Scar

Agree, audiophiles are often too critical with minor details, but oxidation which occurs at the surface of a conductor must be taken seriously. Electrical signal tends to travel at the surface of a conductor, NOT the center of a conductor as some may think.

It's not so bad as you portray. At audio frequencies the signal current flows through the entire cross section of the conductor, with increasing current density as you move out radially from the center. The difference between the current density at the center and that out toward the surface depends on frequency and the diameter of the conductor.

But so what? As I said previously, all the oxide layer does is effectively reduce the diameter of the conductor by a microscopic amount. This will also reduce its cross sectional area which will have the effect of moving a tad more current toward the center of the conductor and ultimately reduce the effect you're speaking of here.

In other words, the current density throughout the cross section will be very slightly more uniform than it would have been otherwise.

One example is the conductor designed by Analysis Plus, they design a conductor which is hollow in the center.

Sure, that's one approach. Or you can just use smaller diameter conductors. The smaller the diameter of the conductor, the more uniform the current distribution through its cross section will be for a given frequency.

Allowing the surface of a conductor to oxidize over time will change the character of the cable and shorten cable life.

Don't see how it would change the character of the cable in any significant way or shorten cable life. Soon as copper is exposed to the air, it soon gets a surface layer of oxidation. This layer of oxidation actually works to prevent further oxidation

Hell, I have a couple of spools of bare copper wire here that are probably going on 40 years old. Still in good shape.

Oxidation is a reason why air dielectric is not used more often.

I would disagree. But if the reason is oxidation, I'd say it's because people tend to irrationally freak out about it just because they've been told by someone that they should freak out about it

se