Here are George Cardas' 2 cents on the subject:
"Q&A with George Cardas
jude: All of your interconnects are made with copper conductors. And in one of your catalogs is the following quote: "Copper has proven to be the best conductor for an audio signal..." Lately there has been a strong emphasis on silver conductors by many cable manufacturers. In general, do you consider copper a better conductor for an audio signal than silver?
George Cardas: In general, yes. We make the majority of all the ultra pure copper and silver used in high-end audio; but I choose to use only the ultra pure, ultra soft copper in my personal products.
George Cardas: For starters, it sounds better. Silver is the best DC conductor, but, embodiment for embodiment, it is more inductive than copper. This trait, combined with its inherently lower loss, accounts for the bright, fatiguing quality of most of the silver cables (silver has approximately 5% more skin effect than copper). There have been many attempts at silver cables but little success. I think the problem in part is the cost of doing a proper conductor out of the metal. By the time the manufacturer buys the metal, there is little budget for a properly designed conductor; so they just use a monofilament solid core. This complicates an already bright situation. Silver is also a relatively hard metal and difficult to anneal. Hard coppers (linear crystal, etc.) also failed because of their tendency to ring mechanically. Electrically, silver is like a speaker box with no damping material. It will be more efficient, but it will have a definite "sound". All in all, your money is far better spent on good conductor geometry and copper.
jude: What is your opinion of silver-plated and/or silver-clad copper as an audio conductor?
George Cardas: Silly. The propagation and transfer impedance of the metals differs and their juncture is diodic. Ensuring a constant transfer is important. Silver and plating make some sense in very high frequency applications, such as video, but are not a good idea in audio."
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