Pareho lang daw ang oxidation rates, e.
OFC is copper that was de-oxidized during the smelting process.
Historically, the "oxygen-free" spec arose from industrial applications where chemical purity is required to prevent unwanted chemical reactions. An example is an application where the copper material will be subjected to temperatures high enough to produce hydrogen embrittlement, such as during soldering.
In copper wires, hydrogen embrittlement can arise when ordinary industrial copper is soldered in an open environment, where the hydrogen in the air diffuses into the copper and reacts with the internally dispersed Cu
20, producing internal holes that make the copper brittle.
However, whether the speaker wire uses oxygen-free copper or not, the wire will still oxidize at more or less the same rate, any difference in oxidation rates being too slight to be significant.
My theory is that changes in the copper could be caused by a chemical reaction between the wire and the insulation material, rather than by the oxygen in the copper itself.
Audioholics says:
Pursuing the Truth: The fact of the matter is that OFHC copper and pure unalloyed copper, both oxidize at around the same rates. Some cable manufacturers use the OFHC as an advertisement that it will not oxidize, or it will oxidize less than other copper conductor materials, but there is no truth to these claims.http://www.audioholics.com/education/cables/component-video-cables-the-definitive-guide/component-video-cables-the-definitive-guide-page-3As for the chemical purity differences between OFC and ordinary copper, the speaker wire authority Roger Russel says:
Oddly enough, it isn't the freedom of oxygen in copper wire that makes any difference. The process of removing oxygen also removes the impurity of iron and it's this impurity that can cause the resistance to be slightly higher. The difference in resistance between copper wire and oxygen free copper wire is too small to be significant for speaker wiring. It can be considered to be ordinary copper wire as far as the recommended lengths of copper wire in the table. Oxygen free copper wire can be more expensive than ordinary copper wire.http://www.roger-russell.com/wire/wire.htm#oxygenfree===================================
Personally, I would still recommend OFC cables not because they are "oxygen-free", but because the ones with OFC specs tend to have better quality,
e.g.: higher quality construction and insulation materials.
