@holmz - lets start be looking at the process at different points in the audio system
At the speaker
- the power required to satisfy the volume level selected has two components - voltage, and the current drawn, which is a product of the speaker impedance
The amplifier circuit
- so the amp circuit attempts to build a voltage signal that will operate the speaker at the required volume and the speaker places a current draw on circuit which must be satisfied (ultimately) by the power supply
- if there is enough energy reserves in the power supply, the signal is created as it should be, with the required voltage and current to move the speaker cone to its required displacement
- if there is not enough energy reserves to provide the required current then the peak voltage is not achieved - and performance suffers
- and ALL of this has to be achieved in the blink of an eye
The power supply
- is always replenishing it’s power reserves via the power cable
- the faster the power cable is at conveying electrical energy, the faster the power supply can replenish energy reserves and satisfy the demand of the amplified signal
- But on the mains supply side of the power supply, the voltage is simply 120v flip flopping at 50 (or 60) Hz as you pointed out
- However, if you could plot the current draw on the mains side, it too varies in a similar fashion to the musical signal, so when the bass guitar slaps or the bass drum beats, the transient spike is in the form of current drawn and not voltage.
So those mono-blocks with the massive power supplies are more able to handle transient spikes in the signal.
However with smaller components, the power supply tends to be less capable, so connecting a quality power cable to a source component will appear to provide more of a benefit than connecting that same power cable to an amp
For best performance
- amps require the very best power cables in order to observe noticeable improvements
- source components will provide more of an improvement with a power cables that is perhaps a little less capable than those selected for Power Amps
So, when selecting power cables for any component I look for those that use UP-OCC copper, because it will provide excellent dynamic response. Silver is better, but a lot more expensive.
But, bear in mind that all of this is all happening at lightening fast speeds, so even in the best mono-blocks - good power cables will improve their performance.
Hope that helps - Steve