The Korg MS20 has a unique place in history in that it was one of the first (and last) affordable 'semi-modular' synths available. It also shares a place with the Roland TB303 'BassLine' in that it's 'sound' was derided upon its release but has now reached almost cult status.

Essentially, it was a pre-patched 2-oscillator successor to the 1-oscillator MS10. However, on the right of the panel was a patchbay of 1/4" jack sockets that allowed you to insert patch cords and 'interrupt' the pre-patched signal/control paths. In many respects, the concept was not unlike that pioneered on the ARP 2600 but where the MS20 scored was its price - it was a lot cheaper.

However, many regarded the MS20 (myself included!) as a poor man's 2600 and it was dismissed as a bit of a toy synth and side-by-side with a MiniMoog, the poor old MS20 did sound a bit wimpy by comparison. But the MS20 found a great deal of favour with those on a budget who couldn't stretch to a 'proper' synth such as the aforementioned 2600 or MiniMoog and as a result, the MS20 was a big success for Korg in the mid-70s when it was released.

On the surface, the MS20 had a modest complement of 'modules' but on closer examination, you'll find two VCOs, two self-oscillating filters (one lowpass and one highpass which together can be configured as bandpass or notch-reject filters), a versatile sample+hold unit, two envelopes (one AR-type with variable note-on delay; another ADSR-type with variable hold time), an LFO with variable symmetry waveshapes, a noise generator (with simultaneous white and pink noise), an assignable modwheel and more. Damn - the thing even had a pitch-cv convertor! On their own, these would have probably been enough to secure some degree of success for the humble MS20 but the addition of the 35-way patch bay opened the way to some outrageous experimentation that elevated the MS20 above many of its contemporaries.

Of course, then as now, a synth was measured by the tone of its filters and it has to be said that the MS20's 12dB/Octave filters did sound a bit limp and fizzy compared with the MiniMoog's beefy 24dB/Octave 'ladder' filters or ARP's 4075 24dB/Octave filter found in their Odyssey - the sound of the MS20's filters were simply not the fashion back in the 70s and early 80s!

However, musical fashion is a fickle thing and the sound of the MS20 became favoured by many including William Orbit and Vince Clarke amongst many others - the MS20 even provided the foundation for the music used in the 'Flat Eric' Levis commercial! Nowadays, most manufacturers of modern analogue synths go to great lengths to provide an authentic 'Korg filter' in their module line-up and what was once considered by many as a weak and feeble pretender is now a highly regarded part of our modern sonic vocabulary.

Korg pursued the concept with the MS50 - a keyboard-less modular synth expander that retained the basic components of the MS20. They also developed a step-sequencer, the SQ10, in the same cosmetic style.