Power cords are the first component in the musical chain.
This statement is counter intuitive to some because power cords do not carry the musical signal. However, the energy output by your audio system must equal the energy supplied. Since the power cord is the energy supply cable, it fundamentally affects the amplification of the music signal. These factors define your system's dynamic potential, i.e. its ability to supply the required energy to faithfully amplify a musical signal. These dynamic contrasts can occur instantaneously.