I have three dedicated lines, one for power conditioner for everything but the amp, another dedicated for amp, third is spare. All three 20amp, 10 gauge Romex, and all three dedicated ground wire to new grounding rod, All grounding wire must be same exact length, including whole house ground, so no grounds potential issues.
I much prefer my amps direct into wall, I've had seven amps here over the past ten years or so, all better straight into wall
Also nice to segregate digital from analog, switching power supplies will contaminate, at present I use linear power supplies exclusively with all my digital components, so no issues here.