asp307,
The question should be what impact will a 20 amp dedicated branch circuit have on the sound you hear from your audio system.
IF your audio system is now being fed from a 15 amp convenience outlet branch circuit, that more than likely is wired using #14awg wire.
Factors to consider:
Age of the existing branch circuit wiring?
What other loads are connected to the branch circuit? It’s not unusual to see lighting loads connected to the convenience outlet branch circuit as well. Any dimmers on the lighting of the branch circuit?
At what point in the length of the branch circuit run is the wall receptacle connected to the branch circuit? What is the length of the #14 gauge wire from the wall duplex receptacle to the electrical panel?
What is the wiring method used for feeding in and out of each outlet box for connecting the wall duplex receptacles to the branch circuit wiring? Is the in and out hot and neutral conductors jointed, connected, together and then pigtailed out for the duplex receptacle connection to the branch circuit? Or was the receptacles used as the connection junction point for the in and out hot and neutral conductor wiring? Was the side terminal screws used to make the connections, or was quick stab in the back side of the device used? What is the conductivity condition of the connections? Any corrosion?
What differences should you hear with the new 20 amp dedicated branch circuit using 10-2 with ground NM-B cable?
Lower noise floor.
Tighter deeper controlled bass.
Cleaner highs.
Fuller mid range.
More air, open sounding.
Just an all around better sound presentation from the power amp.
NOTE: If you bought the Rhodium receptacles I hope you bought them pre-cooked, burned-in. If not you probably will not like the sound you will hear from your audio system. Don’t blame it on the new 20 amp dedicated branch circuit. It will be the fault of the Rhodium plating on the contacts of the new receptacle not being burned in.
IF you have 2 dedicated branch circuits installed, when the electrician is finished with the job and the two circuits breakers are turned on have the electrician show you at the two wall duplex receptacles branch circuits, (with his volt meter), they are fed from the same Line, leg, from the electrical panel.