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Roland System100M

Modular Synth (Retro) By Chris Carter
Published April 1995

At a time when a modular synth could cost as much as an average house, Roland's System 100M was an affordable dream. Chris Carter gets patched in...

I may be showing my age, but it was with the release of Walter Carlos' Switched On Bach (1968) and The Well Tempered Synthesizer (1969) that I really became aware of the synthesizer as an instrument — the sound, the look, knobs, switches, patch cords... I was hooked.

So began my quest for a modular synth. To begin with I wanted a Moog, although systems by Roland, ARP, Korg and EMS were all contenders. Then I discovered that the price of even a medium‑sized Moog system could literally be as much as a semi‑detached house. This may have been fine for Walter Carlos, Keith Emerson or Tomita, but for struggling semi‑pros with a day job, buying one was about as likely as winning the pools.

I had been building electronic circuits since I was at school, so I decided to try my hand at some audio circuits. I searched electronics hobby magazines for circuits, and based my first attempt on designs by Tim Orr (of EMS) published in Wireless World, plus some from Practical Electronics. It had a keyboard, three VCOs, a VCF, VCA, EG, LFO, white noise and reverb — the works. It was temperamental, the VCOs were unstable, the VCFs were weak, and the keyboard tracking was abysmal. But it worked (just).

By the time I had built my sixth or seventh synth, I was using dozens of different circuits connected by yards of wiring. It was built into a four‑foot sloping cabinet and included two pin‑matrix patch boards (like the EMS VCS3), a 16‑step analogue sequencer, a ribbon controller, a joystick, and a separate 5‑octave keyboard. It could even be run off a car battery if needed. By this time I was regularly performing live, and the synth, although versatile, just wasn't reliable or robust enough — it had to be totally retuned and often rebuilt after a gig.

An encounter in 1978 with a reliable and relatively stable EMS VCS3 led me to the conclusion that, after building (or rebuilding) dozens of synths, I needed to buy an 'off the shelf' synth if I wanted a dependable, decent‑sounding instrument. I started with a little Korg 700. Although it sounded fine, I was soon frustrated by the lack of controls and upgraded to a Roland SH3A and a Roland 104 analogue sequencer to control my DIY synth. Over the years I worked my way through the Roland Sseries of synths: SH3A, SH1, the magnificent SH5, the duophonic Roland SH7, SH2 and finally an SH101.

These various combinations worked fine until I discovered Roland's System 100M. I had already tried the System 700; the 100M sounded just as good to me, and offered great build quality, beautiful filters and damn fine oscillators. It was much cheaper than the System 700, but still quite an investment for a basic two‑VCO, two‑VCF, two‑VCA setup. But two things persuaded me to go for the 100M: first of all, the modules were available separately, so I could build a system gradually as finances allowed. Secondly, I had discovered a range of very high‑spec kits utilising SSM chips (as used in Sequential's Prophet 5) from a new UK company called Digisound. To begin with, they had just a few kits available, but the inputs, outputs, CV specs and power requirements were all identical to the 100M. In theory, Digisound kits could be used alongside the System 100M without any problems, at a tenth of the cost of the Roland equivalents. I devised a cunning plan.

Mix 'N' Match

I began by getting two racks, but only four modules — a 112 Dual VCO, a 110 VCO/VCF/VCA, a 140 Dual EG/LFO, a 182 Analogue Sequencer, and the Model 181 4‑octave keyboard. I then mounted a few Digisound kits onto thick aluminium panels, cut to the same dimensions as the 100M modules. This mix 'n' match setup worked perfectly and sounded great. Over the next couple of years I built about a dozen more Digisound modules (VCOs, VCFs, EGs, Envelope Followers, Ring Modulators, and so on). For some, I even sprayed the front panels the same colour as the 100M to fool myself into thinking they were Roland — sad man. Eventually I added three more Roland racks and five more Roland modules: another 182 Sequencer, a 172 Phase/Delay, a 121 Dual VCF, a 130 Dual VCA and a 131 Mixer.

I've been using my hybrid System 100M/Digisound system for about14 years, live and in the studio. Fingers crossed, none of the modules has ever given up on me. Some of the sockets and controls on both the Roland and Digisound modules are beginning to show their age, which can make tuning a little problematic, but they couldn't really be described as unstable, just touchy. Some of the LEDs have died and the Roland DIN‑to‑DIN cables have a tendency to spontaneously self‑destruct, but so far nothing has been beyond repair. And the beauty of a modular system is that if one module develops a problem I can fix it without the rest of the system coming to a standstill.

I used to control my 100M with a clunky 181 keyboard, but sold it with the intention of buying the 184 polyphonic version — though I had so much trouble getting hold of one, or any other 100M modules for that matter, that I eventually gave up looking. Luckily, I still had an ageing Roland SH101 that I modified by fitting a Roland‑style 6‑pin DIN socket to connect to the 100M rack; the socket supplied CV and gate signals to the rack, and the rack fed power to the SH101. Sadly, the 101's keyboard recently ceased working and seems almost impossible to get fixed. Sequencers I've used for controlling the System 100M are the Roland 104, Roland CSQ100 and CSQ600 digital sequencers, and currently the MC8 Microcomposer and TB303 Bassline, both sync'd to a TR808.

Summing up, I have to say that I find the Roland 100M to be as versatile, expandable and affordable a system as you can get without going the DIY route. (Although building your own modules is a great way of cheaply expanding a system.) Given the space and the cash, you can build any combination imaginable — and believe me, there are some big 100M systems out there, with upwards of eight racks and 40 modules. Well, I suppose I'll just have to keep buying those lottery tickets.

The Modules

Between 1978 and 1985, Roland produced 13 modules, two racks and three keyboards for the System 100M, although they had plans for at least five more modules. The 100M racks have an internal buss network that carries CV, gate, trigger and power to all the modules via 8‑pin DIN leads. All the VCO and VCF modules have their first CV modulation slider wired to the keyboard CV buss. The EGs also take their gate and trigger signals from the keyboard gate and trigger busses, and all LFOs have their switchable phase sync wired to the trigger buss. All of these connections can be overridden by inserting a jack into a module's relevant socket.

When a keyboard is plugged into the front 6‑pin DIN socket or if any CV, gate or trigger signals are plugged into the front‑panel mini‑jacks, they are fed through the rack's internal buss system. By linking more racks with the rear 6‑pin sockets, a lot of unnecessary rack‑to‑rack patching can be eliminated. However, the front and rear 6‑pin DIN sockets aren't exactly the same as each other: the front carries two power lines, which the rear version omits, allowing the 100M rear 6‑pin DIN sockets to directly connect to the Roland System 700 and to the MC8 Microcomposer's 6‑pin CV/gate output sockets.

For those of you new to the System 100M, here's a description of each module, with its 1985 list price.

  • 110 VCO/VCF/VCA £210
    This module contains all the elements of a single synth voice. The audio signal paths from the VCO to VCF to VCA are all made internally, as are the keyboard and EG inputs to the VCF and VCA. These connections can be overridden by inserting a jack into the relevant socket. A few features are missing, but that's not surprising, considering the module's 4X9‑inch size.
  • 112 Dual VCO £220
    This module contains two independent VCOs with expanded features; both have a range from 32' to 2', three modulation inputs, and a sync input and output. Three waveforms are available, as is Pulse Width Modulation. These VCOs are pretty stable, with a very wide range. If they are cross‑synced at their higher ranges, they make a nice impersonation of FM synthesis.
  • 121 Dual VCF £190
    Each VCF is a ‑24dB/octave low pass type with a built‑in, fixed, high‑pass filter that's switchable between three cut‑off frequencies. Each VCF has cut‑off frequency resonance sliders that can send them into oscillation. With a beautiful high end and a gut‑rumbling low end, these VCFs sound incredibly rich and musical compared to most digitally generated filters. Use two in series, set to a different cut‑off frequency, for an even deeper effect.
  • 130 Dual VCA £175
    Each VCA can be switched between linear and exponential modes for different amplitude curves and percussive effects when used with the EG. Each has an initial gain control, which also allows the VCAs to be used without a modulation input and as 3‑channel audio mixers.
  • 131 Output mixer/oscillator/Headphone Amp £175
    This is a basic, 4‑input audio mixer with a level and pan control for each channel. The separate stereo headphone output has its own level control. The tuning oscillator provides 22Hz, 440Hz, and 880Hz tones.
  • 132 Dual CV/Audio Mixer & Voltage Processor £160
    This useful module can be used for summing CVs from various sources and/or for audio mixing. Each half includes four sliders for level and an inverted output. Separate sliders are included for providing variable positive and negative voltage sources.
  • 140 Dual EG & LFO £180
    This module provides two ADSR EGs and a single LFO (with five selectable waveforms). Add this module to the 110 module and a CV keyboard and you have all the elements of a basic synthesizer.
  • 150 Ring Mod/Noise/S&H/LFO £180
    A versatile module that provides full ring modulation and sample & hold facilities, white and pink noise generation, and an LFO (the same as featured in the 140 module). The 150 is great for random sequences or controlling the VCF cut‑off frequency while synced to the 182 sequencer module, and the Ring Modulator is the obvious choice for making a racket.
  • 165 Dual Portamento Controller £155
    This is a basic module with two independent portamento (glide) control sections. Apart from CV control inputs, an MPX input is included for switching the portamento on/off from an MC8 or MC4 Microcomposer.
  • 172 Audio Delay/Phaser/LFO/Gate Delay £210
    Another versatile module that features a five‑step phaser (with resonance control), 512‑step 'bucket brigade' delay (also with resonance, for flanger effects), a gate delay (doubles as a pulse shifter) and an LFO. The gate delay can accept most types of signal (audio, gate or trigger pulses within a wide frequency range), which it reshapes and outputs as a 0‑15V gate.
  • 173 Signal Gate & Multiple Jacks £125
    There are a total of 38 sockets on this module; it allows you to turn on or off audio or control signals patched between other modules, automating certain patch alterations.
  • 174 Parametric EQ £155
    This is a single‑channel, four‑band parametric EQ. Each band has level, bandwidth and frequency controls, plus a bypass switch.
  • 182 Analogue Sequencer £200
    This nifty little sequencer offers single‑channel/16‑step or dual channel/8‑step operation. Add modules to increase the number of steps. A full range of controls make the 182 surprisingly versatile.
  • 180 32‑key Controller Keyboard, £210
    181 49‑key Controller Keyboard £275
    184 4‑note Polyphonic Keyboard £490
    The basic 180 keyboard offers tuning and portamento knobs and a position transpose switch. Connect directly to the 100M via a 6‑pin DIN socket, or mini or standard jacks. The 181 adds an extra 17 keys, plus a centre‑sprung bender control and a portamento on/off switch. The 184 is the best specified of the 100M keyboards, with an improved action. It has all the features of the 181 except for the 6‑pin DIN socket, and adds an arpeggiator.
  • 190 Three‑Module Rack £155
    191J Five‑Module Rack £230
    Originally, the racks came as self‑assembly units. The only differences between the two racks, which contain power supplies and all the connectors, are the number of modules they hold and the 191J's front‑panel 36‑jack patchbay. The front panel also featured two pairs of lined mini and standard jack sockets that are connected to two phono sockets at the rear. The sockets on the rear of the racks often get overlooked but can be very useful for linking signals to other racks and saving on patch cords.

Master Plan

Looking through Roland catalogues, manuals and press releases over the years, I've uncovered various references to modules that, to my knowledge, never made it past the drawing board. Has anyone ever come across any of these modules, or prototypes?

111 VCO and VCF.

120 VCF and VCA.

141 Dual Envelope/Gate Delay/Inverter‑Adder.

160 Computer Interface.

170 Pitch to Voltage Converter/Envelope Follower/Amp.

I'd really be interested to know if anyone has!

Experimental Corner

    'Bowing' is a little‑known ring modulator effect that I first came across in the 1970s. A constantly variable voltage source, such as the CV from a pitch bend, joystick, foot pedal, slow ADSR or slow LFO, is fed into one input of the RM and any audible signal is fed into the other input. Depending on how well the RM is calibrated, there should be no output until the the voltage source begins moving — similar to a VCA, but with the difference that the output level varies with the speed of change, not the voltage level. Adding a VCF to the output of the RM and using different combinations of audio and CV sources for the RM produces unusual 'bowing' and 'blown' effects. Alternately it could come in handy as a substitute VCA.
  • LFO as EG
    If you have the 182 sequencer and are running short of EGs, an extra EG can be found lurking in the LFO. The key to this trick is matching the sequencer and LFO speeds — if the sequencer rate is 6, set the LFO rate to 6. Plug the sequencer gate output into the keyboard trigger input, set the LFO delay to zero and the keyboard sync to 'on'. For a standard EG attack/decay type output select a falling ramp waveform, or a rising ramp for a reversed effect. Selecting a triangle or sine wave output is equivalent to a slow attack/slow decay EG output. You can now use the LFO output as if it were an EG. By setting the LFO rate slightly higher than the sequencer rate, you can also achieve some nice polyrhythmic effects.
    It can be impractical to make notes of every connection and setting of a really complex modular synth patch. A quick and reliable solution is to take a series of photos of the setup. If you make sure that everything is well lit, it's even possible to use something like a Polaroid.
    When working on new patches, I often find that I just keep on adjusting and re‑patching, hoping to refine the sound a little more and eventually realise that I've lost a fab sound that I had 10 minutes ago. If you have a DAT machine and a sampler, it's worth connecting up the DAT to your mixer before you start programming. Load it with a 2‑hour tape and keep the DAT machine remote control handy. When you start programming hit record, and shoot index points at your DAT machine every time you produce a good sound. Afterwards you can go back to the index points on the tape and sample the sounds. Not an ideal solution, but at least you have something to show for all that knob twiddling.
    On the subject of sampling, it's often said that samples of analogue gear arew no substitute for the real thing. Well, they probably aren't, but a lot of people (and a lot of sample CDs) get it wrong by sampling individual notes. Even multisampling doesn't always sound right. One of the things that makes analogue sound so good is the movement and fluctuations in the sound, and you only really get this 'feel' over a period of time. I've found that the best way to capture analogue feel more authentically is to sample whole bars of sequences or keyboard parts. If you have the sample RAM, then it's worth trying at least two whole bars (the more the better) and also sampling subtly different versions of the same part, alternating each one on playback. If you want to go all the way, you could run your original analogue sequences alongside the sampled versions for a really rich effect.

Buying Second Hand

Until a couple of years ago there was a regular market for the Roland 100M, with partial and complete systems making regular appearances in the music press classifieds. But for about a year or so the only systems I've seen for sale have been at shops or specialist retro dealers, a privilege for which you usually pay a premium. (A trawl through the dealers revealed that a highly useable five module setup comprising dual VCO, dual VCF, Dual VCA, Dual EG and S&could cost in the region of £1500, but don't quote us! — Assistant Ed.), which isn't actually a lot more, per module, than when they were new. But all is not lost: the occasional single module turns up in the most unlikely places, for ridiculous prices. How about a Roland 150 Ring Mod/Noise/S&H/LFO module for a tenner? True, at a boot sale last year. I've heard similar stories about finds in old music shops — but never seems to happen to me. Last year, in Belgium, I found a 172 sellotaped into a cardboard box; as soon as I showed an interest, the guy decided it was worth £250. But seriously, keep your eyes peeled: you never know what could be under that pile of old plates and socks.

Brief Glossary Of Acronyms

  • VCO: Voltage Controlled Oscillator
  • VCF: Voltage Controlled Filter
  • VCA: Voltage Controlled Amplifier
  • CV: Control Voltage
  • RM: Ring Modulator
  • EG: Envelope Generator
  • ADSR: Attack, Decay, Sustain, Release
  • S+H: Sample and Hold
  • PWM: Pulse Width Modulation
  • HPF: High Pass Filter
  • LED: Light Emitting Diode
  • PSU: Power Supply Unit
  • DIN: Small multi‑pin connector
  • dB: Decibels
  • DC: Direct Current
  • V: Volts
  • Hz/kHz: Hertz and Kilohertz
  • EQ: Equaliser
  • EMS: UK Synth manufacturer
  • ARP: US Synth manufacturer

Making Do

Should you manage to get hold of a module but haven't a rack to power it, there is a solution. If you can handle a soldering iron, then something like the Maplin +/‑15v (100ma) PSU should suffice (part number LP88V). You need to make up a lead with an 8‑pin DIN plug (part number FJ91Y — see connections list below) at one end to supply the module. Warning! Don't attempt to connect a 100M module to anything other than a Roland rack unless you are confident that you won't damage the module with an incorrectly wired plug or PSU. Mistakes can be expensive.

System 100M 8‑pin DIN plug connections are as follows:

  • Pin 1 PSU +5v
  • Pin 2 gate
  • Pin 3 no pin
  • Pin 4 LED +
  • Pin 5 Trigger
  • Pin 6 PSU ‑15v
  • Pin 7 PSU ground
  • Pin 8 CV
  • Pin 9 LED ground

While we're on the subject, here are the connections for the 6‑pin leads that link 100M racks to other racks or keyboards; use Maplin part number HH29G for the 6‑pin plug. If you're linking racks, don't connect pins 1 and 2, but use all pins when connecting a 100M keyboard.

  • Pin 1 PSU ‑15v
  • Pin 2 PSU +15v
  • Pin 3 gate
  • Pin 4 trigger
  • Pin 5 PSU ground
  • Pin 6 CV

The M Word

With the proliferation of MIDI‑to‑CV converters, from cheap single‑channel units to sophisticated multi‑channel types, it has never been easier to control older equipment over MIDI [for the lowdown on MIDI‑CV conversion, see Tom Carpenter's article in SOS last month]. Models like Kenton's Pro 4 are ideal for use with modular systems. An alternative, but less sophisticated, route is to use a Roland TR626, TR707, TR727 or TR909 drum machine. All have a MIDI input and a trigger output that could be used to trigger a sequencer or EG.