One or two dedicated AC wire ?

I want additional circuits, but my main electrical panel is not spacious enough. I don’t want to sound like a salesperson now, but all I need is a tandem circuit breaker right?

Thanks, I will search for a tandem circuit breaker.

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.

sns  Thank you