Sunday, July 13, 2014

More About Power Cords

I wanted to cover a variety of Power Cord related things in this post.
UP-OCC Copper Wire

Teflon and Cold Creep
Firstly I want to say a few things about safety and our power cords. Questions were raised on a forum, although the person doing the questioning was a rival manufacturer with more expensive cords to sell, who knew nothing about how our cords are constructed.

Anyway, the point raised was 'cold creep', a problem that Teflon can have. This is a phenomenon where a plastic (or other material) deforms under the influence of stress over time. It's not a mystery and the rate and extent of creep can be (and has been ) analyzed and graphed.

I was aware of the potential for problems when using Teflon insulation for power cords, but took steps to prevent this from being an issue, and also set about testing the robustness of the solution. There's a few places where creep can occur - along the length of the wire of course, if say a heavy amplifier were sitting on the cord, but also by the cable stress-relief glands on the power and IEC plugs.

Along the length of the cable, the conductors are each covered in a cotton sleeve - this resembles a thick sports-shoe shoelace. And where the stress relief occurs on the plugs there is an additional thicker layer of cotton and also heatshrink.

A number of tests were performed on the wire, both the inside cores (with one layer of cotton) and the finished cords. In one test, the two twisted L and N conductors, with only the one layer of cotton, were gripped by a large Mole Grip such that the wires were being deformed as the distance between the jaws of the grip was about half the diameter of the wire. The mole grip was left on the wire for an extended period (weeks).

This test quite easily shows problems on plain teflon wire, but with the cotton sleeve there was barely any damage and certainly no loss of insulation integrity. 

In real life, the cords have an additional, (thicker) cotton sleeve over the top, making it even harder to damage. Of course we don't recommend that you treat your power cords like this.

Why Teflon?
Others asked "Why use Teflon on power cords? The arguments about dielectric absorption don't apply as there's no signal going down the power cord"

The simple answer to this is "Because it sounds better" .. In fact it's the same reason for the white cotton sleeve, the black heatshrink over the filters.

I've been trying some UP-OCC wire in power cords. I managed to get some 11AWG OCC copper wire with Teflon insulation, and I've been listening to them for a week or more.

How to describe? More dynamic. Lower Noise Floor. But mostly more real sounding.

I did find that I had to add a couple of FIRST kegs to get the sound nicely balanced. So I have just put these on the main website and in the store so they are now available.