RMI began producing the 300 Series Electra-piano in 1967. As with earlier instruments, the Electra-piano featured an oscillator for each key. It uses an
LC oscillator to generate the sound, as it produced a stable frequency that was not prone to drift. The signal is then run through a series of
filters in order to produce an
envelope resembling that of a piano. The Electra-piano also had an "organ mode" that allowed each note to sustain indefinitely instead of decay like a piano, and an "accenter" that added a percussion effect to the start of each note being played. The original 300A (1967) and B (1969) models had 61 keys (
G to
C). The 368 was introduced in 1972 and added seven additional notes at the top end. It was the best-selling Electra-piano. The 368X (1974) was a 368 housed in a molded plastic case instead of the previously used
tolex-covered plywood. The 68D was a
touch sensitive version of the 368X; it was made to order and few were produced. The Model 400 was a console version of the 300, which was intended for the home and club market and included a self-contained speaker system. The 400A (1970) used the same internals as the 300B, adding a 50 watt amplifier. The 468 (1972) was based on the 368. The 600 series combined the sounds of the Electra-piano and the Rock-Si-Chord. The first model was the 600A (1968). It included 8' and 4' tabs, which required two oscillators for every key and a separate bank of filters for each footage. The 600B (1970) featured an improved voicing circuitry and a pedal board with two volume and two sustain pedals. The 668 and 668X were the equivalents to the 368 and 368X respectively. The 668X weighed and cost $2,095. It was the last analog Electra-piano remaining in production in the early 1980s. The Electra-piano had a standard
audio jack output, so it could be connected to any guitar or keyboard amplifier. However, RMI designed amps specifically for the instrument. The 140 came with a single
JBL woofer, while the 140A featured a pair of them, and both had a set of dual high-frequency drivers. An optional accessory was available that was particularly good at producing high frequencies, that sat on top of the amp and was nicknamed the "Hi-Scream Cone". In total, around 10,000 RMI Electra-pianos were sold. However, unlike the Rhodes and Wurlitzer, RMI pianos have been reported as hard to find by collectors.
Samples of RMI instruments are available for digital keyboards such as the
Nord Stage. The
Roland JV-series
sound modules include a "Keyboards of the '60s and '70s" library, which includes a series of RMI samples programmed by Nick Magnus. == Other products ==