The MS-20 architecture truly stands the test of time in
terms of both sonic flexibility and ease of use. The signal path is
fairly standard—two oscillators into a pair of filters into a voltage
controlled amplifier—but its execution is unique. Technically the MS-20
Mini is a semi-modular synth, which means that you don’t need to
use the patch bay to get it to make sounds. However, you can opt to,
overriding the default signal path for deeper sonic experimentation.
Each oscillator offers a slightly different set of
options. Oscillator 1 includes triangle, sawtooth, and variable-width
pulse waves, plus a noise generator. Oscillator 2’s waveform options are
sawtooth, square, narrow pulse and “ring mod,” which is actually
derived from a combination of the two oscillators’ pulse waves but in
practice sounds quite similar to true ring modulation.
The oscillator levels are controlled by a simple mixer,
which in turn feeds a pair of resonant filters in series: a highpass
followed by a lowpass. Hardcore vintage geeks will be pleased to know
that the lowpass filter circuits are based on the original MS-20 filter,
designed in-house by Korg. It’s worth noting that later in the run of
the original MS-20’s production, Korg switched to an off-the-shelf
filter circuit that wasn’t quite as beefy, so the duplication of the
original circuit is a big plus of the MS-20 Mini.
At this point, we should delve into the sound of
the filters, because while other vintage synths—notably the Roland
Juno-6 and Jupiter-8—also include highpass and lowpass filters in
series, nothing in the history of analog sounds quite like the MS-20’s
For starters, the MS-20’s highpass filter is fully
resonant, which means you can do a couple of really cool tricks with it.
If you’re a bass fiend, maxing out the resonance and tuning the
highpass cutoff to the range of your bass line delivers a massive
low-end wallop, with a truly incredible overdriven character.
Alternately, if you’re a fan of filter sweeps, you can hear each
harmonic pop out as you slowly raise the cutoff. What’s more, the spots
between the harmonics come so close to oscillation that you can use the
highpass filter to add “ghost” sine wave tones, creating the illusion of
an additional oscillator.
The MS-20 Mini lowpass filter is equally beefy, with the
same kind of overdrive and oscillation characteristics that make you
feel like the whole synth is going to explode if you push it too far.
With both filters at full resonance, I was able to generate sweeps and
morphing effects that were far more grungy than any other analog synth
in my rig—and let’s just say I’ve got a bit of a collection going.
Modulation sources include an LFO and two envelopes. The
LFO offers a cool little twist, in the form of a continuously variable
waveform generator that can smoothly sweep between ramp and triangle,
delivering far more clever animation possibilities than the usual
triangle-square-saw trinity. What’s more, it also offers an alternate
mode that utilizes a variable-width pulse instead of the ramp options,
accessed via the modular section.
The two envelopes are configured slightly differently.
Without touching the patch bay, envelope 1 is hardwired to pitch only
and includes an initial delay time, attack time, and release time. This
is great for adding everything from little pitch blips at the beginning
of a sound to Afrojack-inspired “dirty Dutch” sweeps.
Envelope 2 controls the amplifier and both filters. It
features the classic ADSR design with the inclusion of a hold
segment—which is great for adding a bit of Moog-like punch to patches.
It’s also a fantastic parameter to tweak while a sequence plays,
allowing you to extend specific notes in a very musical manner.
Envelope 2 is also where things get a little tricky with
the MS-20, since it’s also the hardwired envelope source for filter
modulation. The wrinkle here is that the MS-20’s design is unlike any
analog synth I’ve ever encountered—not necessarily in a bad way, but
definitely confusing, especially for new users.
Without getting too far into the technical exotica of
what’s actually going on under the hood, increasing the MS-20’s filter
envelope modulation amount can actually decrease the cutoff
frequency. This is because the sustain level of the filter modulation is
basically inverted from a functional standpoint. That is, if you set
the sustain at full for amplifier enveloping, then turn up the filter
envelope amount, the cutoff frequency will be in inverse proportion (or
thereabouts) to the sustain level. Thus lowering the envelope sustain
level will then raise the cutoff frequency when modulation is in place.
While I was thoroughly befuddled when I first encountered
this, I have to say that I’m glad the MS-20 Mini is set up this way.
Why? Because it makes it an even more colorful tool in my arsenal. After
all, the original MS-20 was designed during the “wild west” era of
analog synthesizers—a time when there weren’t many rules and in order to
stand out from the crowd, a manufacturer had to take risks. The MS-20’s
unusual envelope behavior is a perfect example of this aesthetic and
I’m 100 percent happy with Korg’s devotion to maintaining the integrity
of the original—even if it means a bit of head-scratching at first.
In addition to its stellar and utterly original sound, the
MS-20 Mini is also the first truly affordable modular synth for the
masses. While its implementation isn’t as comprehensive as, say,
building your own modular system from scratch (as covered in our July
2013 issue), the MS-20 Mini is still capable of a wide range of analog
voltage tricks that no other synth in its price range can touch. Better
still, the process of discovering how now-standard synth features were
originally implemented makes it the perfect educational tool—not to
mention a deep well of happy accidents.
Case in point: Sample-and-hold, a.k.a. the “random” LFO
wave shape known from ELP to Prince for its burbling sound. While the
MS-20’s LFO is quite capable in itself, there’s no sample-and-hold
waveform setting on the knob, so you have to make one yourself—by
connecting the output of the pink noise generator to the input of the
sample-and-hold processor, then clocking that processor with the LFO’s
pulse wave output, and finally routing the sample-and-hold processor
output to an oscillator or filter voltage input.
Simpler patching tactics abound, like manually patching
the pitch-bend wheel to the oscillators, or taking it a step further and
rerouting the pitch wheel to control the amount of envelope modulation
to a given destination. You can skim across the surface or dive into
some really deep waters.
Best of all, you don’t have to discover all of the MS-20
Mini’s cool tricks on your own, since Korg includes the original MS-20’s
patch instruction manual. Once you get past the endearingly dated
writing style of the booklet, there’s a ton of really useful patching
techniques lurking within, so you can experiment with the concepts
behind subtractive analog synthesis without feeling totally adrift at
In addition to tons of nifty modular patch points, the
MS-20 Mini also includes a truly remarkable pitch-to-voltage converter.
If you’re enthusiastic about Ableton Live 9’s new pitch-to-MIDI tools,
you’ll lose your mind over this vintage tech that converts any
monophonic (but not chordal) audio signal into voltages that can drive
the MS-20’s synth engine. For example, you can take a recorded vocal—or
saxophone or flute or other synth—and use its volume and pitch
information to “play” the MS-20.
Granted, it takes a little setting up to get everything
working right. There are high- and low-cut filters to zero in on the
most useful frequencies and it takes some detailed tweaking to get the
voltages to track everything correctly, but once you’ve got that nailed,
you’ll be rewarded with the ability to make almost anything you’ve
recorded into your DAW into a control source for the MS-20’s synthesis
Even if you’re feeling lazy and don’t want to fiddle with
getting the settings right, you can still create extremely organic
swoops and burbles that would take forever to draw in a DAW’s automation
lanes. Regardless of your approach, this is one heck of a cherry on the
MS-20 Mini sundae and a wonderful resource for electronic dance music
producers and prog shredders alike.
To say that the MS-20 Mini is a must-have addition to your
rig is absolute understatement. As an analog synth, it’s a stunning
recreation of a big and bombastic legend. As a modular synth, it’s a
treasure trove of voltage-controlled madness for pros and the
perfect educational tool for beginners. As a processor of external
signals, it opens up a world of options for recorded material, whether
you’re just processing audio with its filters or digging deep into the
pitch-to-voltage capabilities. Plus, the fact that it’s got a street
price of around 600 bucks has made it one of Korg’s biggest hits in a
long, long time—which is why it’s still back-ordered after several
months on the market. So get in line now. The MS-20 Mini is truly “all
that”—and a clear Key Buy winner.