This model was updated as the 200A in 1974 and continued in production into 1984. It featured an improved shield over the reed and pickups to reduce mains hum, which had been a problem with the 200. The last version to be introduced was the 200B in 1978. It was externally identical to the 200A but was designed to be powered by a pair of high-voltage batteries and had no internal amplifier or speakers, in order to reduce hum from the instrument.