Audio power amplifier
audio equipment that amplifies the signal strength of a device such as a CD player or an electric guitar, typically for feeding loudspeaker boxes connected to it
An audio power amplifier (or power amp) amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup, to a level that is high enough for driving loudspeakers or headphones. Audio power amplifiers are found in all manner of sound systems, including sound reinforcement, public address, home audio systems and musical instrument amplifiers like guitar amplifiers. It is the final electronic stage in a typical audio playback chain before the signal is sent to the loudspeakers.
The preceding stages in such a chain are low-power audio amplifiers, which perform tasks like pre-amplification of the signal, equalization, mixing different input signals. The inputs can also be any number of audio sources like record players, CD players, digital audio players and cassette players. Most audio power amplifiers require these low-level inputs, which are line level.
While the input signal to an audio power amplifier, such as the signal from an electric guitar, may measure only a few hundred microwatts, its output may be a few watts for small consumer electronics devices, such as clock radios, tens or hundreds of watts for a home stereo system, several thousand watts for a nightclub's sound system or tens of thousands of watts for a large rock concert sound reinforcement system. While power amplifiers are available in standalone units, typically aimed at the hi-fi audiophile market (a niche market) of audio enthusiasts and sound reinforcement system professionals, many consumer electronics audio products such as an integrated amplifier, a receiver, clock radios, boomboxes and televisions have both a preamplifier and a power amplifier contained in a single chassis.
History
The audio amplifier was invented around 1912 by Lee de Forest. This was made possible by his invention of the first practical amplifying electrical component, the triode vacuum tube (or "valve" in British English) in 1907.
Begin with the source’s own compact description: “Audio power amplifier” is audio equipment that amplifies the signal strength of a device such as a CD player or an electric guitar, typically for feeding loudspeaker boxes connected to it. The dossier treats that line as a proposition to test through Audio, power and amplifier, not as a finished interpretation.
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Biographical claims are most persuasive when dates, appointments and relationships can be traced to records created close to the events described. The source revision retrieved here is dated May 6, 2026. The linked authority identifier is Q758907. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1912 and 1907.
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This entry incorporates text from “Audio power amplifier” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.