More is better? In this case more probably makes absolutely no difference and might even be against code depending on the wiring that is already in place. Unless you have an extremely powerful amp and very inefficient speakers there is absolutely no benefit in using a 20 amp circuit. Everything in the house goes back to the breaker box. Running a separate line dose not isolate your equipment from anything. If you have a noise problem get rid of the noisy equipment and get stuff with well designed power supplies that reject/filter noise correctly. This is audio mythology of the highest order. But, if you want to waste money on feel good ridiculousness that is always your option.
Dedicated line questions...
Did a search, but can’t come up with a good answer. I am considering the install of a dedicated line. The general consensus is a 20amp circuit. How does this rectify with a full system designed around 15amp components/cords. I already have PS audio receptacles, and have upgraded/cleaned up all the other outlets on the current circuit, but it is still noisy. Would installing a 20amp circuit require a refit of gear or just 15-20 amp power cords? I don’t run big mono’s and really only need one line. Would a dedicated 15 suffice? Yeah, fairly clueless in this realm.