Axiom Home Page Forums General Discussion Home Theater speaker wire length

Hi Argon,

Copper does oxidize over time when it's exposed to air--you know those rooves made of copper that turn greenish, as well as copper pennies. Where it's exposed at the connection point, electrical conductivity may be affected. You can use a bit of sandpaper to remove the oxidation if you are using bare-wire connections and return the lustre to the copper.

If memory serves, it seems that other forum members have warned users away from Home Depot's bulk generic speaker wire because it seemed to oxidize even under the plastic insulation, which is odd. Even so, that won't affect conductivity through the copper.

Does anyone else recall those posts?

Regards,
Alan

Not surprising, really.

Rob, without going into the full chemical story again, when copper oxidizes(due to atmospheric oxygen)it turns brown and almost looks black as the reaction proceeds(e.g., very old pennies). A greenish color would be due to a reaction with other elements, most notably chlorine. The greenish color reported under some transparent speaker cables isn't due to atmospheric oxygen, which doesn't penetrate the jacket. Apparently some of the PVC(polyvinyl chloride)jackets(most are okay)were unstable and broke down so that chlorine reacted with the copper, forming the green chloride.

As Alan pointed out, oxidation on the end of the wire can be easily removed with an abrasive such as sand paper, or the end can be trimmed and re-stripped.

The linked material by Mr. Russell is an excellent explanation of speaker wiring in general, in addition to the gauge table, and has undoubtedly helped many avoid wire rip-offs the past few years.