I've wanted one of these for as long as I can remember and finally picked one up last year and it hasn't disappointed. I bought this from the owner who'd had it from new and it works perfectly.

To say it's idiosyncratic would be an understatement But once you get your head around that basically you select where a signal is coming from instead of where it's going to, it all starts to make sense It's capable of some truly unique sounds.

It's a reluctant sale and I've enjoyed owning it, but GAS has got the better of me. And to be perfectly honest, this is a pretty big and heavy keyboard and I just don't have the room to have it out all the time so it been getting neglected, And I'm trying to stick to my one in one out rule.

Cosmetically, it's probably a 9 out of 10.would be higher if it wasn't for that scratch down by the output section (See photos)

It's a UK 240V. Model and comes complete with the original Patch and User Manual (the manual is barely holding together but all there!)

Also included is a Doepfer Eurorack U-202 Volts to Hz convertor so you can Sequence it externally

I was going to install the tubbutec SEES MIDI Retrofit but tbh the U-202 just did the job fine.

Bot the filters are multimode, there's ring mod, it's stereo.

I would definitely prefer collection from South London it's (very!) heavy and it's open to UK only. Sorry but I'm reluctant to trust something this old and heavy to couriers without a flight case.

I've attached a link to the most comprehensive YT video I could find (it's not the one that's for sale) but there's plenty of them up there to watch.

Spec from Manual:

KEYBOARD

- 44 keys, 3½ octaves

- High-note priority

- Pitch bend lever with ±1 octave limiter

- Portamento (up to ~4 sec at maximum)

OSCILLATORS (2 x VCO)

- VCO 1 footages: 2', 4', 8', 16', 32', 64'

- VCO 2 footages: 4', 8', 16', 32', 64', 128'

- Waveforms: sawtooth and square (per VCO)

- Pulse width (PW): 50–90%

- Pulse width modulation (PWM): 10–90%, modulated by LFO sine

- VCO 1 can be cross-modulated by VCO 2 (FM-style modulation)

- Modulation sources per VCO: LFO, EG, S/H, External

- Tune: ±65 cents (master)

- De Tune (VCO 1 only): +700 / −500 cents

- KBD / SEQ source switching per VCO

FILTERS (2 x VCF)

- Each filter switchable: High-pass / Band-pass / Low-pass (HP/BP/LP)

- 2-pole (12 dB/oct) with resonance

- Independent cutoff, resonance, keyboard follow, EG depth and

modulation depth per filter

- VCF 1 inputs (selectable): VCO 1 saw, VCO 1 square, VCO 2, Noise, External

- VCF 2 inputs (selectable): VCF 1 HP output, VCO 2 saw, VCO 2 square

- Filters can be routed in series, parallel or split

- Modulation source per VCF: LFO (multiple waveforms), EG, External

AMPLIFIERS (2 x VCA)

- VCA 1 input selectors: VCF 1, VCF 2, VCO 1 sine

- VCA 2 input: VCF 2 / Ring Modulator output (NORMAL / RMO switch)

- Ring Modulator source: VCO 1 or LFO

- Hold / EG switch per VCA

- Independent modulation depth and EG assignment per VCA

ENVELOPE GENERATORS (3 x EG)

Three independent envelope generators, each with KBD / SEQ / EXT

trigger source select and NORMAL / TIME x5 time-range switch.

EG 1 — 5-stage with both positive and inverted outputs:

IL (Initial Level) 0 ~ −5

AL (Attack Level) 0 ~ +5

AT (Attack Time) 1 ms ~ 1 s

DT (Decay Time) 10 ms ~ 10 s

RT (Release Time) 10 ms ~ 10 s

EG 2 and EG 3 — 4-stage (ADSR-style):

AT (Attack Time) 1 ms ~ 1 s

DT (Decay Time) 10 ms ~ 10 s

SL (Sustain Level) 0 ~ 10

RT (Release Time) 10 ms ~ 10 s

- EG 1 also provides an inverted (B) output; EG 2 provides an inverted (D) output

- EG outputs A, B, C, D, E are freely assignable to PITCH, VCF, VCA and LFO blocks

- Trigger modes: LFO / NORMAL, and SINGLE / MULTI

LFO

- Speed: 0.1 – 100 Hz

- Waveforms: sawtooth, square, sine, sample & hold (with noise source)

- LFO speed can itself be modulated by an EG (EG selector + EG depth)

SEQUENCER

- Built-in 8-step analogue sequencer (the feature that distinguishes

the CS-30 from the CS-30L)

- Clock speed: 0.1 – 30 Hz, or external clock

- Step length: selectable 1 to 8 steps

- Per-step pitch knob (Pitch 1–8)

- CLOCK / MANUAL mode (step through manually with the Start/Stop button)

- NORMAL / KBD mode (in KBD mode, Pitch 1 follows the last key played,

Pitches 2–8 transpose from it — effectively transposable sequences)

- HOLD switch

- Sequencer Control Volt and Trigger outputs to drive other synths

CONTROLS — PITCH BLOCK

- Tune, De Tune (VCO 1), EG Selector, EG Depth

PERFORMANCE / EFFECT

- Pitch bend lever (±1 octave at limiter maximum)

- Portamento (~4 sec at long)

CONNECTIONS / TERMINALS

- Outputs: 1, 1+2, 2 — VCA 1 to output 1, VCA 2 to output 2 (true stereo)

- Output level switch: HIGH 0 dBm / 600 Ω, LOW −20 dBm / 600 Ω

- Headphone output

- Foot controller input (for volume control)

- Sequencer Out — Control Volt and Trigger outputs

- Key Volt — IN / OUT

- Trigger — IN / OUT

- External signal IN (with sensitivity switch 0 / −20 dBm)

- External Trigger Level — triggers on 60 mVp-p min

POWER & PHYSICAL

- Power source: AC 50 / 60 Hz

- Power consumption: 40 W

- Dimensions: 978 (W) x 330 (D) x 173 (H) mm

38½ (W) x 13 (D) x 6-13/16 (H) in

- Weight: 15 kg / 33.0 lbs

NOTABLE FEATURES (in context)

- Effectively semi-modular without patch cables — the input selectors

on VCFs and VCAs let you reconfigure the signal chain (series,

parallel, split, ring-modulated) entirely from the front panel

- True stereo output via two independent VCA chains

- Built-in 8-step sequencer with CV and trigger outputs that can also

drive an external synth

- Three full envelope generators (one of them a 5-stage with negative

initial level — well suited to pitch modulation)

- External input can be processed through the filters, or used as a

modulation / trigger source — making the CS-30 usable as an effects

processor for guitar, electric piano, etc.