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Analogue Systems Sorceror

Modular Analogue Keyboard Synthesizer By Paul Nagle
Published October 2000

Analogue Systems Sorceror

West‑Country company Analogue Systems have been in the vanguard of modern modular synth construction for several years now, most notably with their RS Integrator system. Using Integrator modules, they've produced their first freely configurable keyboard modular. Paul Nagle sees if the spirit of patchable modular keyboards is alive, well, and living in Cornwall...

When I were a lad, the closest I ever came to owning a modular synthesizer was a Korg MS50. It cost me a year's savings and consisted of a pre‑determined collection of modules, but I nevertheless spent many a happy evening in my bedroom playing with its single, unstable oscillator. Relax, I'm not descending into gushing nostalgia; my point is one that we thirty‑somethings make all the time: you've never had it so good. I can't think of a period when so many affordable analogue modulars have been available at once, can you?

At the forefront of this new wave are Cornwall‑based Analogue Systems, offering a wide selection of the synth modules from their RS Integrator modular, or complete, customisable systems. The latter range from the truly jaw‑dropping Phoenix or merely outrageous System 8500 down to more affordable 'starter' modulars. Falling somewhere between 'outrageous' and 'starter', is the imaginatively named Sorceror, a keyboard‑based modular cabinet with integral power supply, 16‑bit MIDI‑to‑CV converter and joystick controller.

Walnut Trip

The Sorceror's back panel, with its built‑in MIDI‑to‑CV converter and rotary selector for determining MIDI channel.The Sorceror's back panel, with its built‑in MIDI‑to‑CV converter and rotary selector for determining MIDI channel.

The review Sorceror arrived in a battered‑looking box, packed with bubblewrap and old newspapers. I was concerned for the safety of its contents but fortunately my fears proved groundless. The Sorceror is constructed from a substantial chunk of American walnut three feet long and 16 inches deep. Yes, it's real wood and has the weight and good looks to prove it!

In common with Doepfer and the unrelated company Analogue Solutions (of Concussor fame), Analogue Systems build their modules to the HP (Horizontal Pitch) Eurorack standard, and the Sorceror's sloping control panel has 168HP of module space to fill as you wish. This is equivalent to the company's own 6U RS15 case but the Sorceror's wooden body lends it a considerably more luxurious appearance. Analogue Systems include a separate power board for up to six Doepfer modules, so this HP Sorceror (sorry) would be an ideal base unit for a mixture of modules from different manufacturers.

Patching Up

The Sorceror is fitted as standard with the RS220 joystick and the RS330 Keyboard Control modules, both positioned to the left of its four‑octave keyboard. For the purposes of this review, Analogue Systems fitted a typical selection of modules, the basis of a powerful monophonic synthesizer. As many of these have been covered in previous SOS reviews (see June 1998 and January 1999); I will concentrate on the Sorceror hardware itself and those modules which we haven't checked out before. Those reviews also contain a glossary of terms that could be worthwhile as a refresher. Having owned an Integrator, I hope you'll forgive me an occasional digression based on personal experience.

As you can see from the 'Modules Used' list on this page, Analogue Systems supplied me quite a<sup> </sup>complement of modules with the review Sorceror, and the more quick‑witted amongst you might notice that the total amount of space required for all of them exceeds that available in the Sorceror itself; I had to remove one of the VCA modules in order to test out the functionality of the RS340 and RS350 (a VCA measures 12HP, but each of the latter modules is six HP).


My first surprise was a pleasant one — MIDI — not something you'd necessarily expect to find built into an analogue modular synth. Nevertheless, the Sorceror's rear panel is equipped with MIDI In, Out and Thru sockets. The MIDI channel is set via a small rotary selector, labelled from '0' to 'F' representing channels one to 16. Once set up (with a mini‑screwdriver), you probably won't need to touch it again as all the resulting analogue voltages are output to the front panel in the RS330 module. This is very convenient and beats having a separate converter with its own adjustment routines, power supply and so on. In fact, I found that no tweaking was necessary as all resulting voltages are perfectly designed to work with the Integrator modules. I should note that the rear panel also features a standard mains connector and on/off switch. It would have been nice if several quarter‑inch jack sockets had been placed there too for audio output (Integrator modules use 3.5mm mini‑jacks), patched through to the front as on the AS System 8000. I suppose if you can operate a drill, you can probably accomplish this yourself with the help of an RS250 Trunk Line module.

Keyboard Capers

Having had my pleasant surprise, I encountered my only actual disappointment. Before I patched any modules together, I directed the Sorceror's MIDI output into Cubase VST and saw that the keyboard was transmitting its notes — monophonically — with a fixed velocity and no aftertouch. As the RS330 module offers these both as voltage sources, I'd mistakenly assumed that the Sorceror's own keyboard could supply them. With no manual to refer to, I double‑checked by cabling up a basic synthesizer voice (VCO, ADSR and VCA) and patching the velocity output to the oscillator's pitch. No matter how hard I hit the keyboard, the pitch didn't change proving that, to fully exploit the Sorceror's magic, an external MIDI controller must be part of the equation. This is a shame, because the built‑in keyboard has a light, fast action that is ideal for solo duties.

Of course, not everybody has embraced MIDI, and doubtless some purists will point out that classic analogue synthesizers of the past managed perfectly well without touch sensitivity. However, the RS330 module offers a number of control points for which MIDI is the only source and consequently, I spent much of the review period triggering it that way.

RS330 Keyboard Control

Since the RS330 is the cornerstone of the Sorceror system, it merits detailed examination. It has no less than five Control Voltage (CV) outputs (each identical), dual Trigger and Gate outputs, and even an S‑Trig output. S‑Trig appeared on Korg, Yamaha and Moog synths and is actually a Gate signal, albeit one with opposite polarity to those of most other manufacturers. It might also have been worthwhile to include a Hz/Volt CV output because, unusually, the Integrator's LFOs can be played in tune from a Hz/Volt source.

I patched the CV outputs to the two supplied RS90 oscillators and reached for some of my own extra long patch cords in order to connect the gate signals to the envelope generators. I made a mental note that if this were my system I'd probably relocate the envelope modules, bringing them closer to the RS330. When I mentioned this to Analogue Systems, they said they were already considering internal connections for the keyboard signals to oscillators and envelopes to save on patching. Usefully, the RS330 has a CV input: add a voltage here and it is mixed with the CV outputs. Thus, with a single cable, you can connect an LFO and add vibrato to each oscillator. Furthermore, if you are making use of the Sorceror's MIDI output, this incoming CV is translated into pitch‑bend.

We've already seen that incoming MIDI notes are translated into CV and Gate outputs — this is what we'd expect of any MIDI to CV converter. The Sorceror, though, has more tricks than that: five other types of MIDI event, when received, appear as voltage outputs on the RS330 panel. These are velocity, aftertouch, modulation wheel and two other MIDI controllers (CC11 and CC12). This provides an excellent degree of flexibility as you can route these to any voltage inputs on the modular that you wish. Performance‑wise, all sorts of interesting options open up. Oh, I nearly forgot, an LED flashes when MIDI data is being received.

Currently, both internal and MIDI control favour lowest‑note priority. Thus, if you hold several notes, the lowest is the one that plays (for more on priorities, see this month's instalment of Synth Secrets, on page 178). Apparently, highest‑note priority can also be arranged. The RS330 has three more settings, in the form of switches, which govern keyboard behaviour. The KBD Trigger switch determines whether the keyboard (or MIDI note) will initiate a new gate signal for each note played (multiple triggering) or whether it will only kick off a gate signal if another note isn't currently held down (single triggering). The Transpose switch shifts the range transmitted by the Sorceror keyboard by an octave up or down. Finally, the portamento switch, which affects the keyboard or incoming MIDI notes, has three positions: on, off or single‑shot. Single‑shot is lightly sprung so you can introduce portamento quickly then release it. Setting portamento to 'on' introduces (guess what) a slew to the CV output signal, the amount of which is set by the Portamento knob.

At all times, the built‑in keyboard takes precedence over any MIDI input — a feature you might use to interrupt sequenced playback, perhaps. The disadvantage of this behaviour is that there is no way to obtain keyboard control signals separately from those sourced in the MIDI/CV converter. I'd like to have been able to transpose incoming MIDI notes and sequences using the Sorceror's own keyboard but, alas, the only way I could see to do that was to use a different voltage source, such as the joystick.

RS220 Joystick

The RS220 Joystick module is indeed a joy to use, featuring a sprung stick that returns to the centre when released (it's also available unsprung or even sprung in just a single direction, if required). Moving the stick in the horizontal direction (the X plane) transmits a voltage between minus five volts and plus five volts. Similarly, moving the stick vertically (that is, in the Y plane) generates up to plus five volts when pushed forwards and minus five volts when pulled right back. Both X and Y voltages have twin output sockets and independent range knobs to fine‑tune the voltage level produced. Thus, you could set up a subtle pitch‑bend in one direction and a wild filter sweep in the other. Joysticks are great, and there's nothing to stop you installing several of these RS220s in your modular system and breaking free from the 'synth=keyboard' tradition. Go on, I dare you.

RS340 Gate Delay

Another newbie to AS, the Gate Delay, has appeared in modular synthesizers since the earliest days. Like all the best building blocks, it is simple in function, generating a delayed gate signal and trigger pulse from an incoming pulse. A positive input between one and 20 Volts kicks the module into life. It's also one of the prettier Integrator elements in those 'lights‑out' moments (such as on stage...?), having LEDs for both delay time (green) and gate‑on time (red).

Other than flashing at you, the RS340 has many practical uses, ranging from the creation of syncopated envelope triggering to delayed clocking of sequencer steps, which can aid the construction of complex rhythms. Since you can use it to generate gate signals of a specified length, it is handy when triggering sound effects that must last for an absolute duration. And, since the input signal has such a wide voltage range, it may be used to produce triggers and gates from incoming audio signals. A small switch determines whether triggers are initiated by every incoming pulse or whether the current cycle must finish first. So if you set a long gate time, you can quickly swap from a lengthy drone to many rapid pulses by flipping this switch. Finally, you can reset the module using an incoming voltage. This is ideal for cutting short a lengthy drone, or maybe chopping up the gate signals with an external sequencer (or audio source).

RS350 Slew Limiter

Portamento is included in the RS330 Keyboard Control module, so you might write off the RS350 as superfluous. However, as in all modular systems, each component can perform a variety of tasks. So yes, essentially this adds a 'slew' time to an input voltage and yes, if the output is then applied to pitch it results in that smooth sliding between notes we call portamento. But you don't have to use it that way. Experiment with other control signals — perhaps smoothing the random voltages created in the RS40 Sample and Hold module or even try it with audio sources. A slew generator is, after all, a simple filter.

The module's Slew control knob varies the amount of slew that is applied to the incoming voltage. This is rated between 100mS per volt to a maximum of around two seconds per volt, although in practice, I found the lowest setting still a little high for the subtlest portamento. One advantage it has over the portamento component of the RS330 is the that it gives the opportunity to slew oscillators individually. A buffered voltage output (that is, an exact copy of the input voltage) is provided so patching one slewed VCO then daisy‑chaining the original input voltage to a second unslewed VCO is a doddle. This creates a lovely thickening effect between two oscillators, recalling the uneven glide of another marvellous British synthesizer, the EDP Wasp.

The module presents its slewed output at two sockets — buffered for accuracy. Usefully, it features an on/off input designed so a clock or gate signal (of greater than one volt) halts the slew time, creating a bypass effect. I found if I connected one low frequency sine wave to the CV input and sent a series of rapid clock pulses to this on/off socket, it could be used as the basis of weird, glissando‑like effects. With only the RS350, two LFOs, and a single oscillator, I had more fun than a good catholic boy has a right to when alone. For several hours, I swooped and warbled as if I had several thousand pounds' worth of VCS3 in my studio — or a demented budgie.

<h3>RS310 Reverb/Chorus</h3>

Continuing the established tradition of reviewing each module in turn, we arrive at the RS310, a BBD (bucket‑brigade device) analogue delay line. Since this module has an on‑line manual entry, I can tell you that it incorporates six unrelated 'taps' at random delay points and with differing output levels. The internal clock that drives the module runs at very high speeds giving a delay range of 2.5mS to 150mS (set by the delay time knob). When the variable or fixed CV input is used, this overrides control of the internal clock, extending this range considerably. There's only one signal input — naturally with an associated level control — so to process several audio sources at once, patch them first through an RS160 mixer. You can balance the dry and effected signal using either a knob or CV input, although sadly, it is not possible to obtain only the effected signal without some of the original being present. Returning to the RS330 for a moment, you can use it to add chorus/reverb to any sound in proportion to how hard you hit a (MIDI) keyboard. Simply patch the RS330's velocity output to the dry/effect CV input.

We still haven't reached the limits of the RS310's repertoire. A resonance control (positioned adjacent to the module's Out socket) sets the amount of feedback from the output to the input, building to a ringing self‑oscillation at its maximum setting. The short delay times on offer mean this reverb won't replace a Lexicon — or even an Alesis Microverb — but delays like this one have other equally important uses and, in a modular system, they can be placed anywhere in the signal path. Flanging‑type sounds, chorus, a slightly metallic reverb: all can be achieved with ease. Apply a negative voltage at the CV input and the delay time slows right down, allowing you to create distinct echoes — so the RS310 has many more uses than you think. On the surface this module is marginally less raunchy and weird than my all‑time favourite AS module — the RS120 Comb Filter. That said, the RS310 is still very capable of adding its own Forbidden Planet‑style strangeness, and I've yet to meet a modular owner for whom that would have no appeal!

Other Modules

Amongst the other modules supplied with the Sorceror, I'd like to mention several specifically, despite their having been reviewed before. One of these is the RS110 Multi‑mode filter, whose low‑pass mode sounds (to me) even sweeter than the RS100 'Moog‑style' low‑pass — and that's before we consider the extra functionality of its notch, band‑pass and high‑pass modes. The Integrator envelopes are beautifully specified and have a number of unusual features — perhaps the nicest of these is the Auto‑trigger capability. With this, a switch lets you trigger the envelopes repeatedly without the need for an incoming gate signal. If you set a fast attack and a short decay time, you may be surprised to hear the envelopes' output lurch into the audio spectrum. With CV input control of the decay time, you can produce all manner of pitched sound effects.

Actually, the only weak module, for me, was the RS90 VCO which can output just two waveforms at once and which has a single knob for tuning, albeit with a switch for the range. The oscillator does sound good, though, and has the rarely‑found ability to alter the width of both sawtooth and square waveforms via CV input.


It's increasingly common to see new analogue modulars, but keyboards that provide CV and Gate control are seldom made any more. It is therefore ironic that the Sorceror is blessed with such a keyboard and yet an external MIDI keyboard still offers more control. The supplied MIDI/CV converter works well, offering a selection of control points from an external MIDI source. It's a pity that there is no way to access note information from both the converter and the Sorceror keyboard simultaneously — I hope this is addressed in a future upgrade.

If the Sorceror isn't big enough for you, an even larger system — the Leviathan — is in preparation, housed in a black walnut casing, and with an additional upper rack space for modules, giving you loads of room to house sequencer modules and so forth.

Looks are important and the Sorceror would look good even if placed next to other classic British synths, such as those from EMS. I can't think of higher praise than that! Furthermore, it sounds superb and has a growing number of well‑specified modules, with more on the way. I don't think it's aimed at first‑time modular owners — it's just a little too expensive — but it scores if you consider it as a self‑contained, patchable synth, or as a base keyboard for a modular setup. If you've ever considered checking out modular synthesis, there's never been a better time to do it.

Cables & Knobs

Analogue Systems' use of mini‑jack connectors allows an extremely complex modular synthesizer to occupy a very small footprint. In the Sorceror, the spacing of modules becomes important (certainly if you intend to use the supplied patch cords) because unless your leads are exactly the right size for the job in hand, they dangle over the keyboard. As with the other new, small modulars, once you create a patch, physical access to the knobs becomes difficult. The knobs themselves aren't a bad size but when surrounded by a tangle of leads, it can be fiddly to weave your fingers through the spaghetti and make adjustments to them. A good solution might be to adopt right‑angled leads which would lie flatter against the synth panels.

Modules Used In Review System


  • RS220 Joystick (included in the basic £750 Sorceror package): £110
  • RS330 Keyboard Control (also included; will never be sold separately)
  • RS80 LFO (x2): £69
  • RS90 VCO (x2): £69
  • RS110 Multimode VCF: £69
  • RS310 Reverb/Chorus: £120
  • RS60 Envelope Generator (x2): £69
  • RS180 VCA (x2): £50
  • RS40 Noise/Sample and Hold: £65
  • RS165 Audio Mixer: £35
  • RS160 CV Mixer: £35
  • RS350 Slew Limiter: £50
  • RS340 Gate Delay: £50
  • RS170 Multiple: £19

All Prices include VAT.

Trivia Corner

Now's as good a time as any to reveal that the 'RS' in 'RS Integrator' stands for 'retro synth'. Coincidentally, it also stands for Robert and Simon, the creators.

In The Pipeline...

It is the nature of a modular synth to expand, eating up studio space each time we are tempted to buy new, exciting modules. Analogue Systems have just announced that the RS90 VCO will be superseded by an RS95 module, which will feature a sine‑wave output, soft sync and new graphics. Existing RS90 owners can upgrade for £20.

Other items on the production line include a version of the (previously stand‑alone) FB3 filter bank repackaged as a module, the RS140 MIDI‑to‑CV converter, a high‑quality VU meter, a stereo phase‑shifter and even a CV‑to‑MIDI converter. Radical stuff!


  • Lovely retro appearance.
  • An ideal base for an analogue modular.
  • Can hold enough modules to form a self‑contained, gigging instrument.
  • MIDI as standard.
  • Can house Integrator, Concussor and Doepfer modules.


  • A little expensive.
  • The onboard keyboard can transmit neither velocity nor aftertouch.
  • Cannot use voltages derived from both MIDI and the supplied keyboard simultaneously.


The Sorceror is a classic‑looking analogue controller with plenty of room to pack in the modules of your choice. Offering both MIDI and CV/Gate operation, it will integrate smoothly (pun intended) into any synthesizer‑based studio.