Some of the Zu Cables use a "silver alloy" but my guess is that it would be copper and silver. Their Varial and Wylde interconnects, Ibis and Libtec speaker cables, and Mother and BoK power cords use it. I just put Wylde, Libtec, and BoK cables in my LP-based 2-channel system and like the results very much--lowered noise floor, more dynamic extremes and nuance, more transparency, more fully fleshed out tones, and better rhythm and timing.