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Marion Systems MSR2

Analogue Synthesizer By Martin Russ
Published December 1994

Martin Russ gets his analogue teeth into the Marion Systems MSR2 mainframe and ASM analogue synth module.

Names seem to be one of the main casualties of modern business: Bob Moog lost the ability to put his own name on synthesizers when his company was bought out; Clive Sinclair sold his name to Amstrad; and Tom Oberheim no longer designs the Oberheim synths which bear his name (in fact, Don Buchla, a synthesizer designer with a completely different style, designed the recently released OBMx). What Tom does these days is design electronics for a different company, Marion Systems. The company's first product to catch the attention of the music world was a replacement circuit board, which upgraded an Akai S900 sampler from 12 to 16 bits, but the MSR2 is Tom's first synthesizer product for Marion — and, apparently, the Analogue Synthesizer Module (ASM) is the first of many forthcoming 'modules'.


Although it may look like a conventional 1U, 19‑inch rackmount expander, the MSR2 is described by its manufacturers as a 'Modular Synthesizer', and this is the first break with tradition. Previously, a modular synthesizer has always been one where the individual circuit blocks (like oscillators, filters, envelopes etc) have been separate modules, and you connect them together using patch leads, which is where the name 'patch' comes from. In the rest of the electronics industry, the word 'modular' suggests something slightly different, where you plug complete units into a frame or rack — and, in fact, the old Oberheim 8‑voice was comprised of eight separate Synthesizer Expander Modules (SEMs) which plugged into a large keyboard unit that supplied the power and control voltages to each module.

The MSR2 brings this concept bang up to date. The module is now a complete polyphonic synthesizer (the ASM) and the rack is now an expander box — although Marion Systems call it a Mainframe (borrowing computer terminology) — with space to house two horizontally mounted synthesizer modules (ie. circuit boards). And now the clever bit — the Mainframe contains all the control functions; the display; the buttons; MIDI In and Out; even the audio connections, a mixer and EQ, and so the plug‑in modules are much simpler (ie. lower in cost) than a complete expander. You effectively save the cost of a front panel and all the hardware by filling an MSR2 Mainframe with two modules. So, although Marion Systems are currently selling the MSR2 with one or two ASMs, you could always add to or replace the synthesizer modules at a later date. The obvious purchase would therefore be one MSR2 fitted with one ASM, leaving room for whatever future goodies Marion Systems (and possibly third‑party designers) care to release — they have already hinted at sample playback (presumably S+S, given Tom's background), wavetable synthesis, and even reverb and multi‑effects.

Because the modules can only communicate with the outside world via the Mainframe, it is possible to control the modules in ways that would be difficult with most other expanders. For example, with two ASMs fitted, you can use the MSR2 as a 16‑note polyphonic, monotimbral synthesizer expander, or as an 8‑note, bitimbral expander (or as any other mix of polyphony and timbrality), but you can still use the Mainframe to control the mixing, panning, effects send, and so forth. Although the modules could be completely different types of synthesizer, the MSR2 as a whole can behave as a single unit and can thus be changed from one configuration to another very quickly by selecting a new setup. [This concept should be very appealing to equipment hire companies, who could keep one or two Mainframes in stock but with lots of different modules available to satisfy client demands — Ed.]

Designer Styling?

Marion Systems have obviously taken some care with the front panel. It is a dark grey, gun‑metal colour and reasonably matte in finish, which helps to reduce reflections and so improve readability in adverse lighting conditions. All the panel writing is in white, which again avoids any problems in monochromatic lighting. The LCD is very bright, very clear, and a nice colour co‑ordinated blue. I experienced some problems with the LCD contrast, however: it kept reverting to an almost unreadable setting, but the UK distributor (MXMXCIX) assured me that this had not been reported on any other units.

I was not too impressed with the large paddle mains power switch, which looks rather too easy to switch off by accident, and the data knob seemed overly sensitive — although it does have a very neat system which jumps to zero if you spin it quickly, instead of zipping right through to the opposite extreme. All other synthesizer manufacturers who use data knobs/wheels would do well to implement the same innovation.

Since the MSR2 is intended to house two modules, the design is quite interesting from a mechanical viewpoint. Unlike most rackmounting expander modules and effects units, the majority of the rear panel of the MSR2 does not form part of the casing, being made up from the rear panels of the modules instead. Unfortunately, this seems to compromise the strength of the casing. When the review model arrived it had a serious warp in it — over 15mm from where it should have been. A little careful pushing quickly bent it back into shape, but the panels and overall construction are not up to the standard I would expect for a piece of equipment costing almost £1,000 that might well see use on the road. (Perhaps this 'in‑transit' bending explains why the LCD contrast was misbehaving?)

Sonic Architecture

The Mainframe deals with SuperPresets, which contain the highest 'performance' level setups. These include the following:

  • Global data for the mixer and EQ.
  • Routing for the two MIDI ports to the two modules.
  • All Module data — ie. the allocation of sounds to channels.
  • Up to 50 MIDI messages (per SuperPreset) which can be sent to the modules. These messages can be used to configure MIDI Controllers with default values; send Song Select, Start, Stop or Continue messages to external MIDI devices; even send Program Changes to set up the rest of your MIDI equipment.

There are 50 named SuperPresets, which is probably sufficient for most people — especially since I could not find a way of copying all those MIDI messages from one SuperPreset to another...

Each Module, on the other hand, contains the individual sound patches — called Presets in this case. The Analogue Synthesizer Module, for instance, offers:

  • 200 RAM user Presets.
  • 200 pre‑programmed ROM Presets.
  • 100 RAM‑based Layers, which hold details of four layered Presets with control over the Note Range, Volume, Pan and Octave settings. These Layers can be selected just like any other Preset, and so some of the complexity that normally confuses users has been removed.
  • Four user‑defined Patch Maps, to cope with the 500 Presets available.
  • Four user tunings and four velocity curves, plus a user‑definable velocity curve.

Easy Editing

Editing is relatively easy; I say this because the MSR2 has the traditional two‑row backlit LCD readout which can only display a very small set of parameters at once, and has no real graphics capability. Despite this, using the MSR2 is not that difficult. The button names are well chosen and clearly marked in white, and the Save button is even moulded in red plastic to distinguish it. The only thing I can criticise about the front panel are the Page and Data knobs, which are simply too small and too close together for my liking.

The MSR2 uses the now‑familiar 'page' system where you navigate through pages of parameters with one knob, move a cursor around to select a parameter, and then use the data knob to change the value. Three additional buttons allow you to choose between controlling the Mainframe, Module 1 or 2, and another set of three buttons chooses between selecting Presets, editing them or changing global settings.

This system works well for the MSR2; the quick editing lets you zip between pages easily, and I found my way around the control and editing pages quite quickly. In a world where each synthesizer manufacturer strives to make their equipment completely different to everyone else, by adopting deliberately confusing nomenclature for 'patches', 'parameters', 'functions' and 'voices', the structural organisation of MSR2 sounds and performances is very similar to Emu's MPS keyboard.

MIDI Aspects

The MSR2 has two MIDI In and Out ports, ie. four DIN sockets, but no Thru socket at all. Port 1 is in line with Module 2, and Port 2 is in line with Module 1, whilst the audio outputs follow the modules. Confused? I was, and the clear legending on the top panel merely made me wonder why it was like that.

The power connector uses a 5‑pin DIN plug and socket which looks identical to a MIDI socket — which breaks one of my own design rules: 'never use the same connector for two different purposes'. Thankfully, the MSR2 is protected from inadvertent connection of the power supply to any of the MIDI sockets (see the 'Inside Track' sidebar). The MIDI Ins and Outs are RF‑filtered with ferrite inductors, and use high quality 6N138 opto‑isolators [in other words, they're well above par — Ed.].

The MIDI implementation of the MSR2 is poorly documented in the owner's manual. There is no official MIDI Implementation Chart and no information on the System Exclusive formats used — so I compiled some for those of you interested: see Table 1.

Marion Systems Corporation have a SysEx identity of $00 $00 $59 and their use of MIDI is slightly non‑standard in places: for example, SuperPatches can be selected using Song Select messages, or any (!) MIDI Controller number; and Non‑Registered Parameter numbers are not used for editing internal values. Instead the Mixer and EQ stages can be controlled using 'Undefined' MIDI Controller numbers: see Table 2. The Modulation Wheel Controller can be used to provide an external control for the data knob.


The MSR2 concept is good, though the real world mechanics are a little suspect — and this may have caused the minor problems that I encountered during my review. To my ears, the ASM preset sounds lack just a little bit of gloss and the filters seem a touch lifeless. But then again the ASM is an analogue synthesizer, and they always did come with warts — that's what made them so special. I suspect that some people will love the MSR2 sounds and filters, and will make a good few hit records using them. In a world rushing to get back to its analogue roots, there are a lot of 'me too' cheap analogue synthesizer modules appearing, and even some modern digital 'emulations'. All too often, these are far too squeaky clean and lack any real character. The MSR2, however, offers enough that is different and innovative to make it appeal to the serious analogue synthesizer user, and it has the right design pedigree too.



  • 1U, 19‑inch rack case: 485mm x 355mm x 45mm
  • 2 Data knobs
  • 9 buttons
  • Volume control
  • 2 MIDI Ports (2 Ins and 2 Outs)
  • 6‑input programmable mixer
  • 7‑band stereo programmable EQ
  • 2 external audio inputs to mixer
  • 2 Module ports
  • Backlit 2 x 20‑character LCD


  • 200 user RAM memories
  • 200 factory ROM Presets
  • 100 user RAM Layers (each 4 layers max)
  • 50 user RAM performance memories
  • 8‑note polyphonic
  • 16‑part multitimbral
  • MIDI Overflow

The Inside Track

I always pull my equipment apart (I destroyed an alarm clock as a child by removing the escapement!) and nose around inside, so here are my findings for the MSR2.

The ASM board is larger than I expected, 280 x 280mm, allowing plenty of spare 'real estate' for some quite complex future modules. The Mainframe PCB is split into two, and there are other PCBs for the front panel, bus connectors; plus input and output sockets. The standard of construction is high — not quite up to state‑of‑the‑art surface mount technology, but neat and tidy with obvious attention to servicing details.

The 'digital' mainframe PCB employs a Motorola 68HC000 processor clocked at 8MHz, and the usual complement of ROMs for the Operating System, battery‑backed RAM, and peripheral UARTs/display driver, etc. Near to the UART are some heavy duty 220 Ohm resistors, with a power rating of at least 2 Watts. I assume that these are the MIDI series resistors, and that they are high powered in order to protect the UART from damage if the external power supply connector (a 5‑pin DIN) is plugged into one of the identical‑looking (5‑pin DIN) MIDI sockets by mistake. I would have thought that the extra cost of these resistors would easily offset the cost of using a different connector....

The 'analogue' mainframe PCB has lots of op‑amps and obviously deals with the mixing of the audio signals and volume control.

The ASM PCB has the usual 4053 CMOS switches for routing the control voltages to the individual parts of the modules, and features eight custom 'Marion' chips; presumably the synthesizer voicing chips? There are even some discrete transistors, which is usually the hallmark of a confident designer! Another 68HC000 provides the on‑board processing power, again with Operating System ROMs and some RAM providing the local memory.

Mechanically the MSR2 is unusual. Most 1U high, 19‑inch rack units have a strong construction based around two 'trays' which fit inside each other. The MSR2 needs to provide access to the plug‑in modules, and so the rear panel is missing, which reduces the rigidity of the rear of the unit. The top and bottom covers could be used to improve the strength, if so desired, but on the review model they were just very thin sheet aluminium. If housed in a rack, then this sort of mechanical rigidity consideration does not apply, but many synth expander modules are used in a stand‑alone capacity, often with other equipment stacked on top; in such circumstances, I feel the MSR2 construction is inadequate.

From a production viewpoint, the mechanical design is overly fussy. There are too many bits of metal, nuts and bolts used to fasten it all together, and it must take many operation stages to manufacture. In my opinion, the case is over‑engineered, and therefore expensive to make, whilst failing to resolve the basic problem of rigidity.

Analogue Synthesizer Module

The MSR2's Analogue Synthesizer Module is a comprehensive and sophisticated 8‑note polyphonic synthesizer. It provides two oscillators, three envelope generators, two LFOs, two ramp generators, controllable pan, and an extensive modulation matrix containing 10 'patch cords'. The filters can be either 2‑ or 4‑pole low‑pass with resonance, with self‑oscillation available in 4‑pole mode. The oscillators are called High Resolution Oscillators (HROs), and it's claimed that "they combine a 'VCO' sound with digital stability" — I did not notice it going out of tune, so I have no reason to doubt this claim. The HROs provide a rich source of waveforms: sawtooth, triangle, clipped triangle, variable pulse width, square, and combinations too; they can even be synced together (three settings from soft to hard). The filters can be modulated with HRO2 for FM effects, and you can feed external signals through them.

The VCF, VCA and General Purpose Envelopes have separate triggering facilities, which opens up possibilities like having the VCA on Single trigger for smooth envelopes, VCF on Multi trigger for key clicks, and the General Purpose trigger running from the LFO.

The LFOs can be triggered from envelopes, re‑triggered at a specific part in the waveform cycle, or even used to sample a control voltage somewhere else in the ASM. A global Vibrato Oscillator is available, which saves one LFO and means that you only need to set one vibrato speed. Two ramp generators can produce interesting control voltages, again with lots of triggering and mode selections.

There are eight voice allocation algorithms: Dynamic; Reassign; Rotate; Reassign & Rob; Rotate & Rob; Monophonic; Unison 2; and Unison 4; and you can set high or low note priority for the monophonic mode. Overall, this is a complex and versatile synthesizer with lots of programming potential.

In common with many of the current crop of analogue revival synthesizers, the ASM offers both the smooth 12dB/octave 2‑pole (as per older Oberheims) and the harsher 24dB/octave 4‑pole (Moog, ARP etc) voltage controlled filter varieties.

My personal acid test for filters has always been their behaviour at extremes of resonance, and here the MSR2's 4‑pole filters did not seem to have quite the predictability and consistency of the Oberheim machines that I drooled over in my formative years. For example, if you turn up the resonance so that it self‑oscillates and then sweep the frequency, you should hear the cliched Syndrum sound, preferably over a wide frequency sweep. However, I could not get the filter to stay just on the edge of oscillation, because somewhere along the sweep it would start, and as I turned down the resonance to compensate, I lost the bite elsewhere. I also couldn't quite make the filters go very low in frequency whilst still remaining resonant, which was a tad disappointing. (In 'eeeouw' terms, the 'eeou' is fine, but the 'w' is missing!)

The second test is to put the filters just below self‑oscillation and then pull the frequency down, so that you get a lovely warm and boomy emphasis on bass notes (the classic 'dow' sound!). Sadly, I didn't really like what I heard here either — it was rather too clinical for my taste. This sort of judgement is highly subjective, of course, so perhaps my preferences are unusual.

So what about the Presets? The ASM's 200 ROM sounds cover just about the whole range of traditional analogue 'standard' timbres — from brash, filter‑swept synth brass to resonant, decaying bass sounds. Although the ASM does allow oscillator 'syncing' facilities, there were none of the really extreme sync sounds to be found. Overall there is a good selection of usable sounds, but nothing much that really grabbed me — I still prefer my ageing, UK‑made, Cheetah MS6 and my Sequential Pro‑One. Today's instruments have such rapid development cycles that their initial preset sounds rarely do justice to their full sonic capabilities. There again, if you're thinking about buying an analogue synthesizer, then you probably only want the cliche 'analogue' sounds anyway, and with a little editing, the MSR2 should deliver those easily.


  • Powerful, expandable, future‑proofed concept.
  • ASM board is a capable source of classic analogue sounds.


  • Mainframe plus one ASM is an expensive way of purchasing an 8‑voice analogue synthesizer.
  • Mechanical strength of case and documentation inadequate.
  • No headphone socket.


A bold idea, offering flexibility and great potential for control of two sound modules.