Cheetah Sound Sampler
The Cheetah Marketing Sound Sampler (1986) was an Analogue to Digital converter system that attached to the system bus connection of the Sinclair ZX Spectrum home computer. Its simple design included an audio preamplifier for use with microphones, an 8 bit analogue to digital converter and an audio output amplifier for impedance matching purposes. The software for the unit was written entirely in Z80 machine code and featured a menu driven interface and an ability to play back a recorded sound shifted over a two octave frequency range using the computer's rudimentary keyboard as a piano  keyboard. Although Cheetah Marketing publicised the unit as suitable for home or professional use, the lack of polyphony and the capabilities of the software really limited the usefulness of the product to the low end of the amateur market. Accompanying the main software package, the designers Speedwell Software created a real-time sound processing unit that contained a frequency shifter, sound chopper or Dalek voicebox effect, Echo, reverb and a very strange sound effect called a "Bubbelizer" that was a failed attempt at a phase shifter. The Cheetah Sound Sampler, although crude and cheap, was one of many such electronic  devices that introduced home computer owners to the possibilities of digital recording and the principles of electronic music that was, at the time, still reserved for a relative few who had the resources to buy expensive professional and semi-professional equipment. The Sound Sampler sold relatively few units due to stiff competition from contemporary manufacturers and the poor build quality of the product that was produced as cheaply as possible. References. Online review of the Cheetah Sound Sampler http://www.worldofspectrum.org/hardware/feat33.html