CEM and SSM chips
CEM and SSM chips are analog integrated circuits (commonly called "chips") used in many synthesizers. Curtis Electromusic Specialties. Founded by Doug Curtis in 1979, CEM developed a family of signal processing products for electronic music synthesizers and audio equipment. In 1988, Doug migrated the company to become OnChip Systems. In 2016, it was announced that the CEM3340 VCO had been remanufactured by OnChip using the original design, the CEM3340 RevG. Other manufacturers manufactured copies of the Curtis Chips as well since the patents had expired. Cool Audio produces the V3340 and the V3320. AS ALFA RPAR  released the AS3310, AS3320, AS3330, AS3340, AS3345 and AS3360 in DIP and SMD packages. Solid State Music / Solid State Micro Technology for Music. Solid State Music, later known as Solid State Microtechnology for Music or simply "SSM," was founded by Ron Dow and John Burgoon in 1974, with assistance by Dave Rossum of E-MU Systems. The company originally produced synthesizer chip sets, and provided bare boards for the hobbyist to experiment with early SSM chips. In an unusual pairing, they also produced S-100 bus computer cards, including a Sound Synthesizer Card. SSM was acquired by Precision Monolithics in 1988 , who was in turn acquired by Analog Devices in 1990. New SSM-badged IC's continue to be introduced by Analog Devices, but bear little resemblance to the original SSM line. Several early members of the SSM team reformed in 2017 as Sound Semiconductor to develop audio IC's in the spirit of early SSM products.