The Yamaha CS-20M is a monophonic analog synthesizer that emerged in the 1970s. Featuring two oscillators, a low-pass filter, and various modulation options, the CS-20M provides a rich and distinctive sonic palette. Its 37-key keyboard and compact design make it a sought-after instrument for musicians seeking vintage sounds and analog character. Despite its monophonic nature, the CS-20M has the ability to produce powerful and expressive sonic textures.