The amplifier

In the hi-fi, an amplifier is generally a self-contained box which delivers medium or high audio power to the set of speakers. There is at least one input, but more there are several: one for a CD player, another for the tape deck, another for the radio tuner, and another for the microphone or turntable.

Hi-fi amplifiers are available from the retail and mail-order houses. Input requirements are only few milliwatts; the output can varies up to hundreds of watts. Prices increase with the increasing power output. Some of the amplifiers contain built in tuners, CD players, or tape decks. A simplified hi-fi amplifier forms basis for a public-address system. The massive amplifiers are used by the popular music bands. Such systems uses vacuum tubes, as tubes offer electrical ruggedness and linearity.