My belief is that the amplifier takes electricity from the wall and stores it in capacitors (like big batteries).
The music signal (from a CD player, etc.) is used to modulate a "valve" (a tube or transistor) which results in a mirror image of the input only stonger.
Think of turning a water faucet on just a little then cranking it wide open then turning it back down, etc. This is modulation (only you are using the stored electricity not water).
This "stronger" signal is sent through your speaker cables and is heard (through your speakers) as music.
The music signal (from a CD player, etc.) is used to modulate a "valve" (a tube or transistor) which results in a mirror image of the input only stonger.
Think of turning a water faucet on just a little then cranking it wide open then turning it back down, etc. This is modulation (only you are using the stored electricity not water).
This "stronger" signal is sent through your speaker cables and is heard (through your speakers) as music.