KORG PE-2000

via this auction

"Sometimes named the Poly Ensemble or K-5 or even Poly Synthesizer (named so on the front page of the service manual). These synths were built from 1976 to 1979/80... very early model, this may be of little interest to a musician, but any collectors or synth historians will notice the naming used on presets 1 & 2 (‘Reed Wind #1 & #2’ rather than ‘Organ #1 & #2’ and the older style knobs (ie not MS-20 style knobs found on the later ones)...

From an historical perspective, it is technically the grandfather of the 3 oscillator Korg Lambda and its main feature compared to modern keyboards is that it has a full polyphonic structure. That is, each and every key will make a sound at the same time (if needed). No voice stealing. A full synth circuit for every note, all 48, and @ 3 VCO's each ...that's 144 VCOs [see update below]!!! It’s also worth mentioning that it’s got stereo outputs! JM Jarre's Equinox Part 8 is nearly all done on a PE-2000 if you want to hear an example of it.

Korg build these into a flightcase with a detachable lid which is nice for live gigs or storage.

The "flowchart" is from right to left

The tuning section
adusts the master tune and also allows you to detune the second and third oscillator for a fuller or animated sound. This is the unique part of this machine and the reason for it sounding very different to the other string machines from the same time.

The envelope section
with Attack and Sustain.

The preset section
· Reed Wind(?) 1
· Reed Wind(?) 2
· Chorus 1 (= Choir, not the FX of the same name)
· Chorus 2
· Brass 1
· Brass 2
· String 1
· String 2

You can select one or two of the presets at the same time. But they have to be either #1 or #2 presets being selected together. So I make that 12 presets
The output section
features Volume, Bass and Treble EQ. A useful addition!

The phaser
The phasers rate is variable. If one uses the straight dry output on one side of the stereo field and the output with the phaser for the other side, you get a nice stereo movement to the sound on slow phaser settings. If the phaser is shut-off (full counter-clock turning till it clicks), you get the same signal on both outputs.

The headphone socket
with separate adjustable volume"

Update via Steamy Vicks in the comments:
"Actually, there aren't as many oscillators as you say. Just like its siblings (PS series and Lambda, it's still a divide-down synth - BUT, with individual VCAs per voice - hence the true polyphonic articulation of individual notes."