Thats interesting, as cable length between i strument and amp, and thus capacitance, makes a noticeable difference with guitars and basses. Mind you, the voltages involved are much lower so any change would be far more significant I guess.
guitar pickups are passive, relatively high impedance, so high cable capacitance, poor screening, messes them up, the longer the cable, the higher the capacitance and exposure to noise, putting a pre-amp on the guitar is a simple solution
power amps are low impedance, high current, the main factor is cable resistance, needs to be low enough to not cause appreciable voltage drop or mess up the damping, for longer runs use fatter cable, but copper is an excellent conductor, it doesn't need anything crazy
there have been silly 'audiophile' cables with such high capacitance that they destabilised some amps, but people buying such snake oil get all they deserve
as for vintage, i had my 40+ year old cartridge re-tipped again a few months ago, and rebuilt my equally ancient pickup arm and deck
