(Fr. amplificateur; Ger. Verstärker; It. amplificatore).
An electrical circuit which increases the strength of its input, and normally acts as an interface between an otherwise incompatible input and output. Certain hi-fi systems and large-scale amplification installations feature separate power amplifiers, which drive one or more loudspeakers, and preamplifiers, which boost and match the different electrical characteristics of a variety of inputs; preamplifiers are otherwise incorporated into other devices, such as mixing consoles and stereophonic hi-fi amplifiers. At its simplest the amplification chain can be seen as microphone (or other source)–amplifier–loudspeaker. The rock music ‘amp’ (combination unit or ‘combo’) consists of a portable loudspeaker cabinet containing an appropriate power amplifier and preamplifier. See also Electronic instruments, §I, 5(i).
In certain areas, primarily among hi-fi perfectionists and rock music keyboard players (and for diametrically opposed reasons), the precision or colouration of the sound produced by earlier amplifiers based on electronic valves is still preferred, and continues to be catered for by some manufacturers. In the case of rock music the valve-generated sound was coloured by distortion in louder music, in a manner very different from that produced by transistorized systems.
G. Slot: From Microphone to Ear: Modern Sound-Recording and Reproduction Technique (Eindhoven, 1956, 2/1959) [trans. of Dutch orig.]
T. Cary: Illustrated Compendium of Musical Technology (London, 1992), 7–13
HUGH DAVIES