What caps to upgrade Crown XII 1500 with?

It is extremely unlikely that the increase of those caps as you mention does anything to lower the distortion.
Depending on the wiring and the amp topology, the higher charge current pulses may even increase distortion and noise.

Do not fall into the 'I'm looking for my car keys under the lamppost because that's where the light is' trap!

Jan
 
  • Like
Reactions: BSST