A bigger issue is fast transient signals that exceed the short term capabilities of your amps power supply. This voltage drop in milliseconds adds audible distortion, particularly in a premium system. The combination of a high-quality power conditioner and high-quality power cords noise is to suppress noise.Nonsense. The line frequency is TOTALLY UNRELATED to program demand. The power supply diodes conduct ONLY at the PEAK of the AC line waveform. The capacitor bank supplies the DC. If the capacitor bank voltage drops below output demand, distortion occurs in the output stage. Input stages have typically have secondary regulators and run at lower voltages than output stages.
A power conditioner may remove some HF noise from the line if there is any. Regardless of noise, it will add impedance to the power transformer / AC line interface. For lower power devices like sources and control units, no biggy. For high current devices, the effect varies with the line and transformer impedances AND THE DEMAND. Take home a few power conditioners and a few amps. The number of combinations is PwrCon X Amps. Some improve, some don’t, some have no effect. Move to another location and the game starts anew.
DO THE MATH!!!