The "common" wisdom is that silver works well with tube electronics, copper with solid state. And that that is because silver tends to sound bright, copper warm. But that assumes that tube amps sound warm, solid state bright, therefore tubes with silver and solid state with copper are synergistic matches, possessing complimentary distortions.
But if the goal is neutrality, going down that path leads to a dead end. Change one component, you have to change them all. If your amp is slightly bright, better you find one that isn’t than to get warm cables to offset the amp’s brightness.
So, are silver cables inherently bright, copper ones warm, and tube amps warm, solid state bright? If I’m not mistaken, users of Clear Day pure silver speaker cables find them to be not bright, just very, uh, clear. Same with the pure silver Kimbers, though they might be just a bit too "clear" for solid state that is itself very clear ;-). I don’t think anyone would pair silver Kimbers with a Krell amp! But with a Pass? No problem. Lots of ARC dealers are Cardas dealers, as well as Audioquest.
I bought 50’ of the Western Electric 14g speaker wire (cotton-wrapped tinned-copper) on ebay, from the retired WE employee. About a buck and a half a foot! Gonna try it myself soon, with my tube and ss amps, and ESL and Magnetic-Planar loudspeakers.