Electronic Music Studios (EMS) Polysynthi

Introduced in 1978 as one of EMS's bold late-70s experiments, this synth pushed boundaries with a massive 49-note oscillator bank derived from a single crystal master oscillator, ensuring rock-solid tuning stability right from power-on that few analogs of the era could match.

At its core, two voltage-controlled LFOs with sine and variable pulse waves can modulate each other, the filter frequency, or even trigger the pair of ADSR envelopes, while the keyboard—four octaves with pressure and position sensitivity—frees up from pitch duties to sweep parameters like the standout voltage-controlled analog delay line, switchable between short mode for chorus and flanging or long up to a second for echoes. Sound sources mix triangle, square, and pulse from the poly bank, plus noise and an external input with envelope follower, all routing through a variable-Q filter whose cutoff dances to keyboard, LFOs, or ADSRs before hitting the VCA and stereo out. Controls cluster intuitively in a central sources panel, flanked by modulation blocks and a compact wooden cabinet that feels sturdy yet portable.

Though para-phonic—sharing one filter and envelope across voices—it earned cult status among players chasing EMS's signature weirdness, with fans praising the delay's creative potential and stable oscillators, even if full poly dreams from rivals like Prophets overshadowed it. A gem for vintage hunters wanting hands-on analog magic without constant retuning.