Double Helix Cables has always used, and will always use pure OCC silver and OCC copper.
We do this because these metals do not just have a proven track record in audio cables and in our personal experience, but also throughout the world of electronics, signal transduction, and in science as a whole. Other metals - gold, platinum, palladium, and others are used solely for contact plating, electrodes, or any application where the goal is resistance to chemicals and oxidation. These elements are not indicated for signal conduction in any application, other than in audiophile products where they are used as a bullet point to justify higher prices. Our search of the literature on silver-gold alloys - including a direct consultation with MIT Materials Engineering years ago -- confirms the only scientific finding is that they are poorer conductors than pure silver or pure gold even, and are only suitable as a plating for high-corrosion environments (Aarts and Jarvis, 1954). They do not have any real-world purpose aside from a few academic investigations of their structural properties in the 1950s.
Metals aside from silver and copper have no way to improve signal transduction, and are more likely to cause distortion and uneven response than confer any benefit -- their conductivity is far less than the crudest copper alloys of the 1800s -- approaching that of tin and iron or worse. For this reason, DHC's design philosophy is entirely devoted to cable performance, not following exploitative trends or inflating the bottom line, but creating new developments through experimentation and refinement of our 13+ years of experience.