What Is an Amplifier?
The purpose of an amplifier is to receive a small electrical signal and enlarge or amplify it. In the case of a pre-amplifier, the signal must be amplified enough to be accepted by a power amplifier. In the case of a power amplifier, the signal must be enlarged much more, enough to power a loudspeaker. Although amplifiers appear to be a mysterious 'black box,' the basic operating principles are relatively simple. An amplifier receives an input signal from a source (mobile device, turntable, CD/DVD/media player, etc.) and creates an enlarged replica of the original smaller signal. The power required to do this comes from the 110-volt wall receptacle. Amplifiers have three basic connections: an input from the source, an output to the speakers, and a source of power from the 110-volt wall socket.