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Analogue Solutions Minimodular

Dual-oscillator Synthesizer By Gordon Reid
Published April 2000

Minimodular rack synth.

Analogue Solutions' diminutive Minimodular contains all the necessaries to make up a miniature patchable synth. Gordon Reid arches an eyebrow at this innovative and compact sound source.

Every once in a while you come across something that tickles your fancy. The object in question may be big, flashy and expensive, or it may be small and cheap — the particular fancy-tickler I'm looking at in this review, however, definitely falls into the small and cheap category. It's a million miles from objects of lust such as the Memorymoog, Yamaha CS80, Moog System 55, or modern equivalents such as the Korg Triton ProX and Kurzweil K2600X. Nevertheless, it has a charm of its own.

The Analogue Solutions Minimodular comprises three pieces — two synth modules and the case that holds and powers them — yet it is a fully-fledged dual-oscillator synth. So let's take a look at each piece in turn, and see how they fit together to create what may be the world's smallest true modular synthesizer.

The Case

Do you know the feeling that occurs when you come across an idea so blindingly obvious that you don't know why you didn't think of it yourself? I felt that as soon as I saw the AS0036 case. It's simply a 36HP case (which translates to a diminutive 190 x 165 x 137.5mm hwd) with an internal power distribution board that is itself powered by an external 12VAC 'wall wart'. Three things make it special:

Firstly, it's made of a tough but soft plastic that is very light; you can place it on top of expensive gear without fear of scratches. Secondly, it has no tapped mounting strips; the synth modules simply screw into the plastic mounting blocks that form an integral part of the case, making the AS0036 much cheaper than it would otherwise be. More importantly, this mechanism makes it possible to use the same case as a host for Analogue Solutions' own modules, for RS Integrator modules from the similarly named but wholly unrelated company Analogue Systems, or even for Doepfer modules. Furthermore, this means that you can mix and match any of these manufacturers' products without any of the nasty gaps that occur when you use conventional aluminium mounting strips. Thirdly, the power supply offers four Integrator-style and nine Doepfer-style power sockets, and deli


The Minimodular's sound generator is an all-discrete, all-analogue Dual VCO/LFO module. This remarkably compact unit contains two well-specified VCOs with a surprising range of features and capabilities. For example, VCO1 offers three waveforms — sawtooth, triangle, and square — plus portamento, and the ability to cross-modulate (ie. frequency-modulate) VCO2. The capabilities of VCO2 itself are different but complementary: sawtooth and pulse waveforms, an independent portamento control, a manual pulse-width control, plus oscillator sync of VCO2 by VCO1. Each oscillator offers a volume control, and these also act as level controls for the sync and cross-modulation functions.

In case all this is not enough for you, there are also eight sockets (though sadly for me, these are of the 3.5mm jack variety — I prefer the quarter-inch type, but they would not have been possible on a unit of this physical size). Four of the sockets are pitch CV inputs: one for VCO1, one for VCO2, and two 'mixed' inputs. The next two are real bonuses — independent pulse-width CVs (with an unusual ±12V range) for each of VCO1 and VCO2. Finally, there are two outputs. The first is a mixed output, but this becomes dedicated to VCO1 if you also use the second output, which is permanently assigned to VCO2.

However, this still isn't the end of the module's capabilities, because turning VCO1's tuning control fully anticlockwise will plunge it deep into sub-sonic territories. This makes it possible to use it as an LFO, thus opening up an even wider range of 'sync', FM, and pulse-width modulation possibilities.

When you consider that this module is just 18HP wide and weighs less than a medium-sized bar of chocolate, you realise just how neat and compact a bundle of features it is. I know (and have owned) many revered dual-oscillator monosynths with far fewer capabilities than this.


Analogue Solutions calls the second module in the Minimodular an 'SY01 synthesizer', and you may remember that I described this briefly in my review of the company's Concussor modular drum system (reviewed SOS September 1999). The first thing to note about the SY01 is that it is another pure analogue module using all-discrete circuitry. The second is that despite its low cost, the SY01's filter is a Moog-style ladder network that provides the classic low-pass 24dB/octave roll-off. Furthermore, this filter is fully resonant, so if you increase the resonance to its maximum, the filter will self-oscillate, producing a signal that you can 'play' using the cutoff frequency CV inputs.

The filter itself has three other controls: the inevitable Cutoff knob, an EG Amount control, and a knob marked 'X Mod'. This is a surprise on a module of this price, because it means that you can control the amount of Frequency Modulation applied to the cutoff frequency, providing many more sonic possibilities than you might otherwise expect. Specifically, X Mod makes possible Amplitude Modulation of a signal's fundamental and/or harmonics or, if the filter is self-oscillating, it provides a second source of FM audio generation.

If the SY01's filter is unexpectedly flexible, the contour generator that modifies it (the 'Envelope') is the opposite. It provides just three controls: Attack, Decay, and Sustain on/off. This makes it possible to generate two-stage AD contours (with Sustain off) or three-stage ASR contours (with Sustain on). Unfortunately, it precludes the use of standard ADSR envelope contours.

Likewise, the VCA is a simple affair with a gain control plus a three-position switch that lets you choose between three modes of operation. If you select 'Gate', the external Gate pulse controls the VCA, generating an 'organ' contour with no appreciable Attack or Release times. Alternatively, the 'EG' setting directs the envelope generator to the VCA, providing AD and ASR loudness contours. Finally, setting to 'Thru' permanently holds the VCA at its maximum level.

Despite its diminutive size, the SY01 is far from lightweight when it comes to inputs and outputs. There are two audio inputs (the second of which provides the source for the cross-modulation option), two ±12V CV inputs for the cutoff frequency, and a ±12V CV for voltage-controlled resonance.

As you would expect, the envelope generator has a trigger input, but you might be more surprised to see that there is also a contour CV output and a ±12V VCA CV input, for voltage control of level. Finally, there is a conventional audio output.


At this price, it would be surprising if there were no corners cut, or costs saved. Consequently, the Minimodular has a number of quirks that would be less acceptable on more expensive synths. For example, the envelope generator exhibits a strange two-stage Attack that is particularly noticeable when the Sustain is 'on'. With the Attack set to its minimum, the initial stage is so fast that a distinct 'pop' occurs (this, by the way, is a good thing) — but it then holds for a fraction of a second before ramping up to its final level. I also found that, in Sustain mode, the level would drift up if I held a note for any appreciable time. Staying with the envelope generator for a moment longer, I found that if you have a non-zero Release time, the Attack cycle starts from the point in the Release at which you play a note. This means that, if you play quickly, the Sustain level goes up, and up, and up until it can go no further. Very unusual.

Another anomaly concerns the triangle wave in VCO1. To be blunt, it isn't a triangle, but a slightly skewed sawtooth wave with a significantly faster rise time than fall time. This makes it very difficult to use it as an LFO for natural-sounding vibrato or for rich PWM sounds.

I discussed these points with Tom Carpenter at Analogue Solutions, who duplicated my tests and confirmed that the envelope acted in these ways. He explained that he had never intended VCO1 to be used as a dedicated LFO, and that he had added the triangle waveshaper as an afterthought once he realised how low the oscillator frequency would go. He also said that modifications over the coming months will address this particular point.

In Use

Despite it being, in essence, a modular synth, you can plug the Minimodular in and start playing immediately. This is because Analogue Solutions have pre-patched the combined outputs of VCO1 and VCO2 into the VCF input, just as you would find on a conventional monosynth (of course, plugging into the front-panel input jacks on the SY01 defeats the hard-wired connection). However, this synth's strengths lie in its flexibility, and I soon found myself reaching for the patch cords.

Driven by the 1V/octave CV and +5V Gate outputs of a Roland SH101, I soon found that my favourite Minimodular configuration used VCO1 as an LFO modulating the pitch of VCO2. This converted the Minimodular into a single-oscillator synth with a conventional LFO/VCO/VCF/VCA architecture, and very pleasant it was too. OK, it's no Minimoog, but I was surprised at the number of ARP-ish sounds that I created. Indeed, turning to my 16-channel MIDI/CV converter and playing the Minimodular from a modern workstation, I found it simple to use the VCF and VCA CV inputs to make the Minimodular both velocity- and pressure- sensitive. I was then able to emulate the gorgeous ARP ProSoloist (a synth I deeply love). If you're a fan of brassy patches and buzzy pulse-wave lead sounds, you won't be disappointed with the Minimodular.

Returning VCO1 to conventional duties, the Minimodular produces a fine range of fat dual-oscillator sounds. Mild detune (almost unavoidable given that there are no fine-tuning controls) produces the expected warmth and depth, while tuning in thirds or fifths leads us deep into Emerson and Wakeman territory. Be warned, however, that this arrangement precludes any conventional modulation from within the Minimodular itself. If your tastes are more modern than mine, the Minimodular is an ideal small synth for zooming off into wilder and more percussive territories. This is not surprising, because Analogue Solutions originally designed the SY01 as a drum synth module. Simply set the resonance to maximum and sweep the filter using the 303-ish envelope generator — the results are instant techno. Then hook up an analogue sequencer, add X Mod and... well, you get the picture.

Going beyond this, I soon found myself wishing for extra facilities such as a CV mixer, a CV splitter (a 'multiple') and a more complex envelope generator. Nevertheless, the Minimodular excels at making some pretty wild noises. With careful patching and free use of the sync and frequency-modulation functions, this little box will take you much further than most pre-patched synths. I have no doubt that it would make an excellent noise generator in the same role as a VCS3 (think early Hawkwind or Roxy Music) — and that's high praise indeed.

Then, of course, you can make the Minimodular an adjunct to a larger modular synth. I hooked the review unit up to a Model 8000 RS Integrator from Analogue Systems, and soon found that two extra oscillators with sync and frequency modulation, plus an obviously '70s-style filter, were valuable additions. Indeed, the Minimodular is a cost-effective way to add this many extra facilities to an existing modular synth — you would need at least five Integrator modules and a larger case to exceed the Minimodular's capabilities. Sure, there is a trade-off in terms of quality and flexibility when compared to the Analogue Systems modules, but the Minimodular is still excellent value for money.


It's not often that you find a genuine dual-oscillator synth with two FM sources, sync, dual PWM capabilities, voltage-controlled resonance, plus velocity and pressure sensitivity. As for one in a package as neat and light as this... not a chance. The Minimodular is currently unique.

Of course, not everything in the Minimodular garden is rosy, and you'll find it hard to create many common monosynth sounds on the little box. For example, the lack of a true triangle or sine wave makes it impossible to generate smooth PWM sounds, and the lack of a full ADSR makes it impossible to create many sounds that could be considered part of the standard synthesist's palette. But to concentrate on these limitations is to tell only half the story. I have owned and played highly specified synths that were about as exciting as last night's washing up. In contrast, the Minimodular is fun. More than that, it's lots of fun. With these sounds and at this price, you really ought to check it out.

The Future Of The Minimodular

The Minimodular provides a simple entry point for beginners wanting to get into voltage control and modular synthesis. It's not ideal, because you would really want a wider range of modules and facilities for educational purposes, but as a starting point, and at under £250, you can't complain.

However, you'll soon be able to add extra modules and facilities to the Minimodular, because Analogue Solutions have already announced a number of additions to the range. These include the SY02, which offers a high-pass filter and low-pass filter designed to emulate the Korg MS20's (strangely popular) filters, and an as-yet-unnamed LFO module with sample & hold facilities and a noise source. A little further in the future we should also see the release of the EG02 dual envelope generator, the RM02 dual VCO with ring modulation, and an 84HP plastic case that the company claims will be 50 percent cheaper than its aluminium counterparts.


  • It's small and beautifully formed.
  • It's inexpensive.
  • It can sound great.
  • It's remarkably flexible in some ways...


  • ...but surprisingly less flexible in others.
  • The anomalous behaviour of EG and VCO1 triangle wave needs correction.
  • Its size requires the use of 3.5mm patch leads (my preference is for quarter-inch jacks).


If you are looking for a cost-effective monosynth, a cheap and cheerful entry into modular synthesis, or simply a cost-effective addition to an existing modular setup, I don't think that you can go far wrong with a Minimodular. While it lacks some of the facilities found on other monosynths, it more than makes up for this with unusual features of its own.


£249 including VAT.

Analogue Solutions.