Component stereo systems came to the fore in the post-World War II era to fulfill the demand for high-quality sound in a home setting, matching the improvements in recording and broadcast technology. Users could customize systems, including radio, turntables and tape recorders. An amplifier or receiver usually formed the heart of an audio system, though with different capabilities.
The Development of Discrete Amplifiers
Prior to the 1950s, the gramophone was mechanical, with the stylus sitting in the record groove, coupled physically with the large speaker cones. Electro-mechanical heads replaced these, turning the movement of the stylus into a small electrical signal. Preamplifiers boosted this tiny signal to line level, which power amps then increased further to drive speakers. Features and controls were added, such as loudness controls to compensate for low-level listening, incorporated equalizers and noise reduction.
The Progress of Radio
As component amplifiers developed, the integration of radio into home stereos grew with the introduction and development of FM radio. Since, like LPs and reel-to-reel tapes, FM could supply a stereo signal, it was natural to develop dedicated radio tuners that could connect to the component amplifier to benefit from its sound quality and speaker system. By the early 1960s, a component amplifier typically had RCA inputs to support tuners, turntables, tape recorders and other auxiliary sound sources.
The Transistor Effect
Reliance on vacuum tubes limited how small a stereo component could get, until the coming of the transistor. Reductions in size led to the ability to mate components together, and the receiver came to prominence in the late 1960s and early 70s. Tuners, preamps and power amps were now housed in a single component that, like a component amplifier, could support other audio devices in a single unit. While audiophiles remained faithful to discrete components, the convenience of the receiver, the amp with a radio, caught on with consumers.
The Decline of Component Stereo
The digital age is affecting the way music is played in the home. CDs, DVDs, personal MP3 players, smartphones, radio, LPs and tapes can all provide sound sources. Many people build audio systems around their computers and other digital devices; while hardware supporting those sources sometimes integrates with conventional stereo equipment, much stands alone or with other wireless equipment for multi-room audio from a single source.