The Casio SK-1 is a small sampling keyboard made by Casio in 1985. It has 32 small sized piano keys, four-note polyphony, with a sampling bit depth of 8 bit PCM and a sample rate of 9.38 kHz for 1.4 seconds, a built-in microphone and line level and microphone inputs for sampling, and an internal speaker and line out. It also features a small number of four-note polyphonic preset analog and digital instrument voices, and a simple additive voice. All voices may be shaped by 13 preset envelopes, portamento, and vibrato. It also includes a rudimentary sequence recorder, preset rhythms and chord accompaniment. The SK-1 was thus an unusually full-featured synth in the sub-US$100 (equivalent to $ today) home keyboard market of the time. The SK-1 includes one pre-arranged piece of music, the Toy Symphony, which is played when the "Demo" button is pressed. The Radio Shack version of the Casio SK-1 is called the Realistic Concertmate 500. The SK line continued throughout the late 1980s, including the SK-2, SK-5, SK-8 and 8A, SK-10, SK-60, SK-100, SK-200, and SK-2100.

Use in recorded music

The SK-1 has been used by a few major recording artists for its simplicity and lo-fi sound. It became very popular in the late 1990s among the circuit bending crowd after the first guide to bending it was published by Reed Ghazala in Experimental Musical Instruments magazine, though the SK-1 was being modified as early as 1987 when Keyboard Magazine published an article on adding MIDI support.