Keyboard amplifier

The variation of keyboards, new or older, together with synthesizers, electric pianos including Fender Rhodes and Wurlitzer, have a wide sonic range so that keyboard amplifiers are designed to be distortion free and to provide a more flat frequency response. Since some keyboards may have a wide frequency range, woofers and tweeters may be used for a more flat reproduction.
Amplifiers with speakers for electromechanical and electronic organs don´t neccessarily provide as much tonal range since they have another character in order to suit classic organ sounds with overdrive, key cklick and "growling" as a part of the sound.

Keyboard amplifiers are usually "combo" amplifiers that integrate the amplifier, sound controls and speaker into a single wooden cabinet.

Link:
Some useful info about keyboard amps - sound.westhost.com