Good intentions and bad information about having 2 20amp 120v dedicated circuits & outlets will create a massive ground loop and hum. A 15amp 120v outlet will generally suffice for 2 channel home audio.
If you must add a dedicated 20 amp 120v circuit/outlet in your room....use the following: 1) compatible 20amp 120v breaker for your service panel 2) 12 ga Romex 2 conductor w/ ground 3) 20 amp 120v outlet. Do not increase the wire size beyond 12 ga. as this is a code violation and will not give you better ac quality or quantity.
You should use a large quality 15amp or 20 amp multi-outlet strip with enough outlets to plug everything you require into it. If that is impractical then use identical smaller outlet strips piggy-backed into one another. I have great success using 2 identical Furman 6 outlet 15 amp rated outlet strips.
You can pm me for more advanced instructions to make your system as quiet as possible.