WHAT IS A CONDUCTOR?
An Electrical conductor is an element (remember the periodic table in chemistry?) which conducts electricity, as opposed to an insulator, which does not, or a semiconductor which allows some electricity to pass. There are also alloys that have different electrical characteristics, and platings or other element to element contacts such as in connectors which also have electrical characteristics as well as chemical characteristics in their applications. Simply stated - it is not just a matter of connect metal to metal and you have a good connection. The best connectivity designs take into account the source connector materials, the receiving device connector materials, the audio video wire connector materials, the conductor materials and the electrical and chemical ways in which they interact with one another.
MEET THE CONDUCTORS - SILVER, COPPER, GOLD, TIN, NICKEL, STEEL
1. Silver is the best conductor, with a very slight edge over copper. Silver also has the benefit of having oxidation that conducts as well as unoxidized silver.
2. Copper is the next best conductor, with about 1.05 times the resistance of silver, and due to its lower cost is the most commonly used conductor for audio and video cables. Unfortunately copper oxidation is a semi conductor and should be avoided because of the "skin effect" which causes high frequencies to use the outside of the conductor at high frequencies. If the outside of the conductor is oxidized, the performance at very high frequencies will suffer. Note: This is does not have any significant effect in the audio frequency range. (For more on Skin effect see the Article Library at Audioholics)
3. Gold has about 1.4 times the resistance of copper and does not oxidize making it a popular plating for audio and video connectors.
4. Tin is a poor conductor, with about 8.5 times the resistance of copper, but has good resistance to oxidation and the oxide has good conductivity. Tin is quite often used to protect copper from corrosion.
5. Nickel has about 4.5 times the resistance of copper, good resistance to oxidization and good oxide conductivity. Nickel is a very common connector plating.
6. Steel has about 7 times the resistance of copper, lousy resistance to oxidization and lousy oxide conductivity. Steel is generally used only on high frequency cables plated with copper that need very high strength.