Audio amplifier

[technoguy]

An audio amplifier is an electronic amplifier that works with audio frequencies (generally 20 hertz to 20,000 hertz). It is the final stage in the audio playback chain and its purpose is to amplify the electrical audio signal from its preceding stage to a level that can drive the loudspeaker(s). The preceding stages are low power audio amplifiers which perform tasks like pre-amplification, equalization, tone control, mixing/effects, etc or audio sources like record players, CD players, cassette players, etc. By "low power" it is meant that the signals are usually limited to those required to drive headphones (less than 500 mW).