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RSF Kobol




rsf kobol

audio demo Country: France
audio demo trend price : 2000- 3000€
demo video comments

RSF KOBOL keyboard (1978)

The legendary French monophonic synthesizer made by the great Fernandez team Ruben and Serge Fernandez.


rsf kobol logo

french synth

info KEYBOARD (weight:10 kg) 44 keys.
This main panel features 28 knobs, 5 switches and 15 buttons. On the leftmost part there there are 2 wheels for modulation and pitch control.

Front panel terminal connectors:
- audio out at high / low impedance
- control voltage for VCO
- control voltage for VCF
- gate control
- external audio process line input
- clock trigger input

edit VOICE monophonic machine based on subtractive synthesis.
A voices is composed by 2 syncable oscillators with individual settings:
- 4 octaves height
- volume
- tuning


rsf kobol wave

editOSCILLATORS voice board generates 7 main waveforms with intermediate shapes:
- triangle
- saw
- saw 2X
- various % rectangle pulses

TECH: the waveform transition is smooth and very harmonics.



filter FILTER the VCF is a 4 poles resonant (up to auto-oscillation) filter based on SSM-2040 chip.
A keyscale function on filter can be engaged.

adsr ENVELOPE 2 EG generators each with a 2- stages ADS:

Special bypass switch activates the VCA drone mode.

lfo LFO
a single oscillator (tri / sqr) modulates 2 destinations:
1- VCO pitch
2- VCF cutoff

filter PERFORMANCE some handy functions for:
- glide legato mode switch
- decay on/off
- keyboard octave selector
- cutoff knob

board rsf kobol

lfo CV some stages can be controlled by external tensions (1V/oct) such as:
- VCF filter cutoff
- VCO pitch with GATE

sequencer SEQUENCER a 2X 8 steps with internal frequency rate controlled by relative LFO potentiometer.

sequencer SYNC internal clock tempo can be set using the LFO frequency or sync mode to external +5V trigger input to arpeggiators modules like Elka Synthex or drum machines clocks like Roland Tr-808.

memroy MEMORY :
- 16 memory slots
The memorized sounds can be also be played in sequence rotate, damn nice for some electro patterns also syncable to external trigger input clock. RAM is retained when switched off with a dedicated Cmos-chip like 5101 based board "programmeur" and a battery is soldered to it - just check out for acid leak.

original scan

MEMORY BOARD click to enlarge

5151 memory chip


rsf Kobol Expander

There are various KOBOL releases with different white knobs and a special custom version with.... accordion keys--gosh

rsf Kobol Expander

EXPANDER I the Kobol exists also in rackmount version, with more CV routing but lacks the great sequencer with sound rotate.

EXPANDER II a module add-on with some new features like ring modulation, Sample and Hold, Envelope follower with many CV OUTS.

RSF Polykobol II

RSF Polykobol II (1983) polysynth. A total disaster production and highly unreliable, this doomed machine sents the RSF company out of business. VIDEO


MOS-LAB KOBOL EXPANDER a modern remake.
I did not try this out but seems to be quite expensive. VIDEO

vco kobol MOS LAB 980 KOBOL VCO - clones oscilaltor for modular project
rsf kobol VST RSF KOBOL VST PLUGIN: nothing for now, no samples libraries neither.


RSF Kobol memory test RSF kobol synthesizer
voici l'engin! memory test ZE kobol!

rsf kobol audio demo




We do not have it, but there is an ONLINE version in FRENCH.


IF you HAVE schematics or service for KOBOL keyboard, please get in touch for free sharing.



original scan




original scan




original scan




for sale




raf kobol back panel Lfo made in france


solid solid
rare classic


REVIEW "rare monosynth with incredible sequencer"

manual manual
sound - hard to find
- sequencer


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all snapshots, sounds, texts copyright Polynominal.com / Eric Pochesci

rsf kobol 4 out of 5 based on 14 ratings. price €?