Instrument amplifier

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This page is about amplifiers for musical instruments. See also instrumentation amplifier, a type of operational amplifier.

An instrument amplifier is an electronic amplifier designed for use with an electric or electronic musical instrument, such as an electric guitar.

A wide range of instrument amplifiers is now available, some general purpose and some designed for specific instruments and even for particular sounds. These include:

"Traditional" guitar amplifiers, with a clean, warm sound, a sharp treble roll-off at 5 kHz or less and bass roll off at 60–100 Hz, and often built-in reverb and "vibrato" units. These amplifiers, such as the Fender "Tweed"-style amps, are often used by traditional rock, blues, and country musicians.
Hard rock-style guitar amplifiers, which often include a preamplification controls, tone filters, and distortion effects that provide the amplifier's characteristic tone. Users of these amplifiers use the amplifier's tone to add "drive", intensity, and "edge" to their guitar sound. Amplifiers of this type, such as Marshall amplifiers, are used in a range of genres, including hard rock, metal, and punk.
Bass amplifiers, with extended bass response and tone controls optimised for bass guitars (or more rarely, for upright bass). Higher-end bass amplifiers sometimes include compressor or limiter features, which help to keep the amplifier from distorting at high volume levels, and an XLR DI output for patching the bass signal directly into a mixing board. Bass amplifiers are often provided with external metal heat sinks or fans to help keep the amplifier cool.
Keyboard amplifiers, with very low distortion and extended, flat frequency response in both directions. Keyboard amplifiers often have a simple onboard mixer, so that keyboardists can control the tone and level of several keyboards.
Acoustic amplifiers, similar in many ways to keyboard amplifiers but designed specifically to produce a "clean," transparent, "acoustic" sound when used with acoustic instruments with built-in transducer pickups and/or microphones. (Note that there was once also a brand of guitar and bass amplifier called Acoustic, still seen second-hand.)

1 Role of Amplifier
- 1.1 Size and Power Rating
2 See also
3 External links

[edit] Role of Amplifier

Instrument amplifiers differ from Hi-Fi (high fidelity) stereo amplifiers in design and intent. Hi-Fi amplifiers are designed to accurately reproduce the source sound signals at very high fidelity.

In contrast, instrument amplifiers are often designed to add additional tonal coloration to the original signal or emphasize certain frequencies. For electric instruments such as electric guitar, the amplifier has a major role in the creation of the instrument's tone. Instrument amplifiers that provide distortion (clipping) or dissimilarities between the input and output signals are sought out by musicians in many genres. Many instrument amplifiers for electric guitar and bass allow performers to add distortion by boosting the input signal gain.

The two exceptions are keyboard amplifiers and acoustic amplifiers which are used for amplifying acoustic instruments such as acoustic guitar, violin, mandolin, etc.). Acoustic amplifiers typically aim for a relatively flat response.

[edit] Size and Power Rating

In the 1960s and 1970s, high output power amplifiers were preferred for instrument amplifiers, especially for large concerts, because public address systems were generally only used to amplify the vocals. However, by the 1980s and 1990s, as public address systems became more powerful, the electric guitars, basses, and keyboards were also amplified through the public address system.

As a result, musicians were able to use smaller instrument amplifiers with lower wattage ratings. The switch to smaller instrument amplifiers makes it easier for musicians to transport their equipment to performances. As well, it makes concert stage management easier at large clubs and festivals where several bands are performing in sequence, because the bands can be moved on and off the stage more quickly.