Speaker Wire Corrosion

[jrtm]

I was putting a new AV wall plate in the lounge room today when I noticed that the speaker wire has corroded. The wire was installed in the walls in 2002 or 6 years ago, what would make the speaker wire corrode so badly? And I am talking about all the cable being completely corroded all the way through. 100 meters was purchased at the time.

The speaker cable is “Acoustic Research Pro Series 12 Gauge Speaker Cable” it has a lifetime warranty so I wonder if it will be covered? For the record the banana plugs don’t have any sign of corrosion on them. Below is a URL to a pic I took of the cable this afternoon.

http://i486.photobucket.com/albums/rr229/j...78/damaged1.jpg

Edited September 24, 2008 by jrtm

[Darryn]

I was putting a new AV wall plate in the lounge room today when I noticed that the speaker wire has corroded. The wire was installed in the walls in 2002 or 6 years ago, what would make the speaker corrode so badly? And I am talking about all the cable being completely corroded all the way through. 100 meters was purchased at the time.

The speaker cable is “Acoustic Research Pro Series 12 Gauge Speaker Cable” it has a lifetime warranty so I wonder if it will be covered? For the record the banana plugs don’t have any sign of corrosion on them. Below is a URL to a pic I took of the cable this afternoon.

http://i486.photobucket.com/albums/rr229/j...78/damaged1.jpg

Usually something along the lines of dissimilar metals reacting with each other and causing a battery plate like effect. We call it the "green death" when repairing electrical connections. Additives or differences in either the cable or banana plugs cause a small voltage to continuously break down the weaker of the 2 metals. It's usually very pronounced if there is moisture ingress as well.

Darryn

[fawlty99]

Is it on the surface only? My guess would be moisture and maybe reaction to alcaline mortar?

[jrtm]

Is it on the surface only? My guess would be moisture and maybe reaction to alcaline mortar?

Yep it is surface only, I don't know where the moister would be coming from as there is no rising damp anywhere and we don't have a brick house.

[SHO]

Basically any moisture in the air, of course you can never see it but it would be there. Once the copper/cable is exposed it will happen in most cases.

I beleive contact grease is a good way to stop it from happening.

[jrtm]

Basically any moisture in the air, of course you can never see it but it would be there. Once the copper/cable is exposed it will happen in most cases.

I beleive contact grease is a good way to stop it from happening.

There is a sticky residue that seems to be over the cable, it has always been there, I am guessing that is the contact grease? I have emailed acoustic research to see if they will warrant the cable as supposedly it has a life time warranty. If they say no I will purchase another brand that has corrosion protection.

[fawlty99]

If it's only on the surface then I wouldn't worry about it. Presumably the wire actually attached to speaker/amp is in good condition - i.e. the contact between wire and plug is not compromised.

[myrantz]

Is that green thingie copper oxide?

[jrtm]

Is that green thingie copper oxide?

I would say it is copper oxide yes

[Mr.Bitey]

Looks minty - is it minty? :-)

I rekon ive got some of that cable... ends are corroded (open air), but under the plastic looked ok last time i checked..

Cheers,

Bitey

[myrantz]

I would say it is copper oxide yes

Granted copper oxidises easily, still can't figure out why or how it gets into that level.. And there's no moisture where you live?

Somebody must have dunk it in seawater to get that snake oil effect

[jrtm]

Granted copper oxidises easily, still can't figure out why or how it gets into that level.. And there's no moisture where you live?

Somebody must have dunk it in seawater to get that snake oil effect

Yeah where I live in sunny Bendigo Central Victoria it has been drought here for 12 years, rain here would be equivilent to gold falling from the sky.

[Ozone]

normally when copper oxidises in air it just turns black and wouldnt be affected under the insulation,the crud on this looks more like some acid reaction, either residue from the manufacture of the wire or leaching out of the insulation.

[Mitcon1503562253]

Usually something along the lines of dissimilar metals reacting with each other and causing a battery plate like effect. We call it the "green death" when repairing electrical connections. Additives or differences in either the cable or banana plugs cause a small voltage to continuously break down the weaker of the 2 metals. It's usually very pronounced if there is moisture ingress as well.

Darryn

I have to agree with Darryn as this is what I think is normally the reason behind this. I would certainly be speaking to the people I got the cable from even if it didn't have a "lifetime" warranty. There is serveral stages to oxidation and with copper to get the patina (green) stage it needs to be exposed to water, oxygen, and CO2 in the air form a complex mixture of oxides and carbonates. Now this takes some time on it's own unless the are traces of acids/voltage left that accelerate the oxidation process. To start with the oxidation process of copper bare Cu metal atoms react with air to form the pink colour cuprite (Cu2O). This next slowly oxidizes further to the black stuff, tenorite(CuO). The black sulfide CuS also sometimes forms. In the presence of moisture, the blackish layer slowly reacts with sulfur dioxide and carbon dioxide from the air to eventually form the patina which is a mixture of 3 minerals and gives the greenish colour.

Good cable (heck even cheap cable IMHO) shouldn't have this happen under the insulation and I would consider it faulty if it did. And I do think it can have an adverse affect on the sonic abilities of the cabling as electrons travel most/best accross the surface area of cable. This is why better cables have more stands of wire to any given gauge.