Instrument amplifier in the context of "Band-stop filter"

The violin, sometimes referred to as a fiddle, is a wooden chordophone, and is the smallest, and thus highest-pitched instrument (soprano) in regular use in the violin family. Smaller violin-type instruments exist, including the violino piccolo and the pochette, but these are virtually unused. Most violins have a hollow wooden body, and commonly have four strings (sometimes five), usually tuned in perfect fifths with notes G3, D4, A4, E5, and are most commonly played by drawing a bow across the strings. The violin can also be played by plucking the strings with the fingers (pizzicato) and, in specialized cases, by striking the strings with the wooden side of the bow (col legno).

Violins are important instruments in a wide variety of musical genres. They are most prominent in the Western classical tradition, both in ensembles (from chamber music to orchestras) and as solo instruments. Violins are also important in many varieties of folk music, including country music, bluegrass music, and in jazz. Electric violins with solid bodies and piezoelectric pickups are used in some forms of rock music and jazz fusion, with the pickups plugged into instrument amplifiers and speakers to produce sound. The violin has come to be incorporated in many non-Western music cultures, including Indian music and Iranian music. The name fiddle is often used regardless of the type of music played on it.

Jazz violin is the use of the violin or electric violin to improvise solo lines. Early jazz violinists included: Eddie South, who played violin with Jimmy Wade's Dixielanders in Chicago; Stuff Smith; and Claude "Fiddler" Williams. Joe Venuti was popular for his work with guitarist Eddie Lang during the 1920s. Improvising violinists include Stéphane Grappelli and Jean-Luc Ponty. In jazz fusion, violinists may use an electric violin plugged into an instrument amplifier with electronic effects.

A pickup is an electronic device that converts energy from one form to another that captures or senses mechanical vibrations produced by musical instruments, particularly stringed instruments such as the electric guitar, and converts these to an electrical signal that is amplified using an instrument amplifier to produce musical sounds through a loudspeaker in a speaker enclosure. The signal from a pickup can also be recorded directly.

The first electrical string instrument with pickups, the "Frying Pan" slide guitar, was created by George Beauchamp and Adolph Rickenbacker around 1931.

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.

An electric piano is a musical instrument that has a piano-style musical keyboard, where sound is produced by means of mechanical hammers striking metal strings or reeds or wire tines, which leads to vibrations which are then converted into electrical signals by pickups (either magnetic, electrostatic, or piezoelectric). The pickups are connected to an instrument amplifier and loudspeaker to reinforce the sound sufficiently for the performer and audience to hear. Unlike a synthesizer, the electric piano is not an electronic instrument. Instead, it is an electro-mechanical instrument. Some early electric pianos used lengths of wire to produce the tone, like a traditional piano. Smaller electric pianos used short slivers of steel to produce the tone (a lamellophone with a keyboard & pickups). The earliest electric pianos were invented in the late 1920s; the 1929 Neo-Bechstein electric grand piano was among the first. Probably the earliest stringless model was Lloyd Loar's Vivi-Tone Clavier. A few other noteworthy producers of electric pianos include Baldwin Piano and Organ Company, and the Wurlitzer Company.

Early electric piano recordings include Duke Ellington's in 1955 and Sun Ra's India as well as other tracks from the 1956 sessions included on his second album Super Sonic Jazz (a.k.a. Super Sonic Sounds). The popularity of the electric piano began to grow in the late 1950s after Ray Charles's 1959 hit record "What'd I Say", reaching its height during the 1970s, after which they were progressively displaced by more lightweight electronic pianos capable of piano-like sounds without the disadvantages of electric pianos' heavy weight and moving mechanical parts. Another factor driving their development and acceptance was the progressive electrification of popular music and the need for a portable keyboard instrument capable of high-volume amplification. Musicians adopted a number of types of domestic electric pianos for rock and pop use. This encouraged their manufacturers to modify them for stage use and then develop models primarily intended for stage use.

Dynamic range compression (DRC) or simply compression is an audio signal processing operation that reduces the volume of loud sounds or amplifies quiet sounds, thus reducing or compressing an audio signal's dynamic range. Compression is commonly used in sound recording and reproduction, broadcasting, live sound reinforcement and some instrument amplifiers.

A dedicated electronic hardware unit or audio software that applies compression is called a compressor. In the 2000s, compressors became available as software plugins that run in digital audio workstation software. In recorded and live music, compression parameters may be adjusted to change the way they affect sounds. Compression and limiting are identical in process but different in degree and perceived effect. A limiter is a compressor with a high ratio and, generally, a short attack time.

The krar (Geʽez: ክራር) is a five-or-six stringed bowl-shaped lyre from Ethiopia and Eritrea. It is tuned to a pentatonic scale. A modern krar may be amplified, much in the same way as an electric guitar or violin. The krar, along with the masenqo and the washint, is one of the most widespread musical instruments in Northern Ethiopia and Eritrea.