Good Grief! Just use the power cords supplied by the manufacturer of your audio gear. That is all you need!
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Imagine you have a pair of 100 Watt Class A Monoblocs. Thats 200W. Now, at 30% efficiency for Class A that would come to 600W (a little more including input stage, etc). At 115 volts that comes to 5.21Amps!
It would take 2300Watts of total power to exceed the capacity of a 20Amp AC outlet :-)