JohnnyCanuck
Headphoneus Supremus
You are listening to power itself when you listen to any electrically amplified sound.
Nope. The only time you are listening to power is if you hear a 50/60Hz buzzing.
And just where do you think the current flowing through those gain stages comes from?
Everything is important and nothing is more important than the power supply. Regulators, capacitors, rectifiers, transformers... All of it.
Any non-linearity in the power supply will cause non-linearity in the voltage amplification or current amplification stages.