Speaker Wire Burning

[Ford Flyer]

I have Acoustic Research 12-gauge speaker wires for my home theater. When setting it up, in some places I used rubber bands to keep the cables wrapped together. Now I am moving, and when I was taking apart the system I noticed that wherever I had a rubber band, there is black inside the cable, almost like a burn mark (the insulation is clear). Does anybody know what this could be from? If needed I can provide receiver and speaker information. Thanks.

 

[j_garcia]

Reaction between the PVC and rubber bands.

 

[Ford Flyer]

Do I need to cut out these parts? Will it effect sound quality or anything? The other thing is that the outside of the insulation that is actually touching the rubber bands is fine. The burning is taking place inside the wire. Could a reaction take place like that through the insulation?

 

[j_garcia]

Oops, I didn't catch that INSIDE part. That's an interesting one, but it isn't all that uncommon for PVC to react with the wire inside, so maybe it's just because of the compression caused by the rubber bands that this occured. Whether or not it will affect the sound is hard to say, and the only way to know for sure would be to compare it to another wire. My guess is it probably won't be an issue, but if it makes you feel more comfortable, use new wire.

 

[mtrycrafts]

I have Acoustic Research 12-gauge speaker wires for my home theater. When setting it up, in some places I used rubber bands to keep the cables wrapped together. Now I am moving, and when I was taking apart the system I noticed that wherever I had a rubber band, there is black inside the cable, almost like a burn mark (the insulation is clear). Does anybody know what this could be from? If needed I can provide receiver and speaker information. Thanks.

As j mentioned, it is a reaction of the clear pvc and copper, a surface discoloration by oxides, I believe. Not to worry about it as it is a copper surface condition. Current densities penetrates the cable completely at audio frequencies, unlike Rf where most/all are near the surface or on the surface. And, the signal seeks the least resistance in the wire so it will bypass that bump of increased minuscule resistance. I that color change is not visible or objectionable, continue to use it.