RSF Kobol Expander I & II

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via this auction

"Here is for sale a rare example of a perfectly working RSF Kobol Expander I, one of the most sought after synths of the 80s.  Only around 800 units manufactured! Probably one of the best sounding mono synths ever built. Note this is a 220-240v European voltage model. You must use a transformer to work with 115V US power (transformer not provided).


Some called it the French answer to the MiniMoog, among other great features it has :
1. An incredibly pure and powerful tone, due in part to its high quality components
2. analog morphing waveforms (UA726 Fairchild)
3. SSM filters and envelopes (2040 & 2050)
4. and many others (see below)


It's basically the RSF Kobol only without keyboards and presets but with many patch points and features added :

2 VCOs with sweepable waveforms
2 ADS envelopes
1 LFO (triangle or square)
1 VCF very musically self-oscillating 24db low pass
1 VCA
1 noise generator
1 reversible voltage processor
Decay on/off
VCO 1 modulation off
VCO sync
VCO detune
VCF in
CV/gate 1 volt/octave


The Expander I along with the Expander II (also for sale in my other auction) formed altogether a very powerful modular Kobol, much more powerful than the Kobol keyboard. Imagine what would have been a MiniMoog with so many patch points added !!
Each of these modules is also totally compatible with any vintage modular or semi-modular synth system such as those from ARP, Moog, EMS, Roland, EML, etc. as well as modern modular synthesiser systems from the likes of MOTM, Synthesizers.com, Modcan, Analogue Systems, Analogue Solutions, Doepfer, & all the eurorack variety..."

Expander II

"Here is a very rare example of a perfectly working RSF Expander II rack mount modular synth, companion to the Kobol Expander I (also for sale in my other auction).
Note this is a 220-240v European voltage model. You must use a transformer to work with 115V US power (transformer not provided).
Only around 200 units manufactured!

The unit features :
1 Ring Modulator (selectable between AC or DC)
1 ADSR envelope
1 VCA
1 LFO (ramp/triangle/square)
1 Mixer (3 inputs / 1 ouput)
1 internally or externally clockable Sample & Hold
1 Noise generator
1 Voltage processor (selectable between linear or logarythmic)
1 voltage inverter
1 Gate delay
1 Envelope follower
1 Lag generator
2 Multiples"