At some point early in the history of the ZYX Universe, which according to legend is a "special" model originally developed for USA distribution only, one or more reviewers opined that the copper coil/low output version of the UNIverse was the best sounding of the optional versions, which included, in addition to the copper/low output version, copper/high output, and silver coils with low or high output. (Output is either 0.24mV or 0.48mV, depending on the choice of "low" or "high".) That notion took root among audiophiles, and nearly everyone (including me) bought the copper/low output version. I don't know the story that goes with all the later versions of the UNIverse, of which there are now too many to keep track of, at ever increasing price points. Other than that one instance, I never thought much about purchasing a cartridge based on the conductor used to wind the coils of a cartridge. Like Raul says, it is the overall design that counts far more, in my opinion too. This notion is supported by the fact that there are good and bad sounding cartridges with either copper or silver coil windings. Gold is more rarely ever used, except by van den Hul and one other brand mentioned above. I think in considering the "sound" of a gold coil, we have a difficult time divorcing ourselves from the subjective biases surrounding "gold". Gold "feels" warm and lush, just to use the word.
Koetsu "silver clad copper" is almost for sure not different from "silver-plated copper". I have never liked the sound of ICs made from silver-plated copper, no matter how pure is the composition, because it sounds more bright and edgy to me in my systems than either pure copper or pure silver. On the other hand, Koetsu cartridges, even the ones with silver-plated copper coils, never sound bright and edgy, which brings me to the question: to what degree does the nature of the wire used to wind the coils in a cartridge or in a transformer affect the SQ of the output? I doubt it is valid to think about that without reference to the physics of a coil of wire. For this I refer to Intactaudio's post above. Dave knows more about the electronic behavior of a signal in a coil or transformer winding than any of the rest of us can even dream of. I wonder whether his remarks about the sound of copper, gold, silver pertain to wire in a coil or linear wire. Maybe also Dave could comment on the physical state of the audio signal in a coil serving as part of a transducer, as in a cartridge or a SUT or an output transformer. Folks pay big bucks for silver windings in a SUT or output transformer; are the results worth it?
