Roland SH-3, SH-3A

The SH-3 (1974) and the later SH-3a (1975) were programmable 44-note monophonic synthesizers that allowed for both additive and subtractive synthesis. The difference between the two versions was the filter; the SH-3 used a diode filter, while the SH-3a used a Moog-like transistor ladder filter.