OXYGEN FREE COPPER GUITAR CABLES
From: Shootout Guitar Cables UK • Best Guitar Cables Explained
See also: The Shootout Guitar Cables Range
Copper as an industrial product is considered to be a 100% conductor of electricity i.e. it sets the standard and has the highest electrical conductivity of the non-precious metals; it also has superior tensile properties to, is more malleable than, and is much cheaper than, silver; indeed the purest forms of copper available can approach 103% conductivity.
The electricity distributors and recording and broadcast industries can't all be wrong with their millions of miles of copper wire, but is there 'good' copper and 'bad' copper for guitar cables to carry our precious tone; is there a 'best' copper, does anyone really care and can anyone tell the difference using just their ears?
Perfectly pure copper Cu does not exist no matter how much we refine it (very much in the same way as your studio carpet looks clean after vacuuming so long as you don't use a magnifying glass), and so it is graded, and oxygen free copper is one of the many types of grading.
The 100% conductivity copper standard was specified over a hundred years ago (before the electric guitar was invented) by the International Electrotechnical Commission for 'annealed' copper whereby the copper is heated and cooled in such a way as to even out its consistency and improve its properties in various areas of performance when cold again.
In the following years technology improved upon the annealed specification with 'electrolytic-tough pitch' ETP copper which is 99.90% pure and contains no more than 0.04% oxygen and has the 100% conductivity. This has been used extensilvely for electrical purposes and these days the specification will often be exceeded and manage a conductivity of 101%.
So what's with the 'oxygen free' copper OFC that hi-fi and pro-audio cable makers have been making such a fuss about over the years?
Standard 'oxygen free' copper OFC was developed for purposes where the oxygen in the copper could be a problem for some very specific chemistry related reasons regarding oxygen, but not for conductivity, as it has the same conductivity specification as ETP copper, and a lower general purity than ETP at 99.50% but it does have the lower oxygen content at no more than 0.001% where that is required.
It is only 'oxygen-free electronic' OFE copper that technically speaking at least, is superior in conductivity, general purity and oxygen-free specifications to the others above.
Oxygen free alone means nothing useful, though if a cable specifies '99.99% pure oxygen free' then that should in theory mean 99.99% pure and also oxygen free, or in other words the OFE specification above.
So is the OFE specification (99.99% pure 'oxygen-free') with 101% conductivity a 'good' copper for guitar cables and is it the 'best'?
The purity aspect of a copper guitar cable will mean good consistency for tensile strength and malleability and can give the improved 101% conductivity also so it is a minimally worthwhile consideration for guitar cables which get yanked about so much carrying weak signals, however the diameter of copper used affects resistance, and it is not resistance but capacitance in practise that has the big affect on guitar tone, and a lot of interference and handling noise can mess up the signal too, so all things considered then, shielding along with capacitance are vastly bigger factors to consider than 1% resistance differences between copper types where guitar cables are concerned.
Discussions of copper specification are highly esoteric, and truth be told nobody would be able to consistently hear any difference in blind testing between any of the 100% or above conductivity types commonly used when fabricated in two cables of otherwise identical construction and length.
Also in this guide:
Guitar Cable Capacitance and Resonant Frequency
Guitar Cable Capacitance Chart
Guitar Cable Length and Signal Loss
Guitar Cable Myths and The Cable Fairy
Guitar Cable Shielding and AC Hum
Guitar Cable Microphonics and the Triboelectric Effect
Braided vs Spiral vs Foil Guitar Cable Shielding
True Bypass Pedals vs Buffered Pedals
Silver Plated Copper Cables and 'Red Plague' Galvanic Corrosion
Copper vs Silver Signal Conductor Guitar Cables
Gold Plated Guitar Cable Jacks and Galvanic Corrosion
Guitar Cables vs Guitar Pedal Board Patch Cables
Low Capacitance vs High Capacitance Guitar Cables
Oxygen Free Copper Guitar Cables
Cheap vs Midrange vs Expensive Guitar Cables