An edited version of this text also appears in
SOUND ON SOUND magazine Vol. 10 No. 6. April 1995

Retrospective by Chris Carter


It was the release of the Walter Carlos albums 'Switched On Bach' in 1968 and The Well Tempered Synthesiser in 1969 that I really became aware of the synthesiser as an instrument - the sound, the look, all those knobs, all those switches and all those patch cords, the synthesiser was for me.

So began my quest for a modular system. Of course I couldn't afford a commercial system but maybe I could make one. I had been building electronic circuits since I was at school, these had been the usual run of the mill circuits, and lately had a lot to do with lighting and visual effects for my gigging light show (which is another story in itself), so I decided to try my hand at building some audio circuits. I started searching magazines like Practical Electronics, Elektor and ETI for circuit designs. My first attempt was based on some circuit designs by Tim Orr (of EMS) and published in Wireless World and some more from Practical Electronics. It had a keyboard, three VCOs, a VCF, VCA, envelope generator, LFO, white noise, a built-in reverb, the works! I housed it in a large black box that looked like a mutated Mini Moog. It was temperamental, the VCOs were unstable and the VCFs were weak and the keyboard tracking was abysmal. But at least I had a 'synth' and it worked, just.

Around this time more companies started to appear offering complete kits, parts and circuits for building DIY synths. Some of these kits were just effects units and some were complete instruments. Very inventive names were given to these products. How about Ring-O-Lett, Fuzzarama, Sky-Rider, Miaow Filter, Vibrotron, The Lez-Lee and The Drainpipe. But hey, this was the seventies.

Those of you with long memories may recall companies like Dewrton, Paia, Wilsic, Clef, Powertran and Phonosonics, who all produced synths or effects kits. Dewtron were weird, they encased all their circuits in brown resin so you couldn't see the the PCB design or components used and a company called Tyler sold a lovely little filter that used a torch bulb and a light dependent resistor to vary the VCF frequency, very state of the art.

By the time I had built my six or seventh synth (and none of them modular, yet), I was using dozens of different circuits and kits amongst yards of wiring. It was built into a large four foot sloping cabinet and included two pin matrix boards for patching (like the EMS VCS3), a 16 step analogue sequencer, a ribbon controller, a joystick, a separate 5 octave keyboard and it could run off a car battery if needed.

By this time I was performing live a lot and this synth, although pretty versatile, just wasn't reliable or robust enough. It had to be totally retuned (a big job then) 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 (and rebuilding) literally dozens of synths, circuits and kits I needed to buy a commercial 'off the shelf' synthesiser if I wanted to get a dependable, decent sounding instrument. I started with a Korg 700 synth. Although it sounded fine I was soon frustrated by the lack of controls and upgraded to a Roland SH3A keyboard and a Roland 104 analogue sequencer to control my DIY synth. Over the years I worked my way through the Roland SH series of synths: the SH3A, SH1 that had a nifty external audio input coupled to an envelope follower. I then got the magnificent Roland SH5, the 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 and the 100M sounded just as good to me. Great build quality, beautiful filters and damn fine oscillators. It was substantially cheaper than the System 700 but still quite an investment for a basic two VCO, two VCF, two VCA set-up. But two things finally persuaded me to push the boat out and go modular. The first was that any of the racks or modules could be bought separately, so I could just buy what I could afford and build a system in stages. Secondly, I had come across some very high spec synth kits utilising SSM chips, the same type used in synths like the Prophet 5. The people producing these kits were a new UK company called Digisound. To begin with they just had a few kits available, a VCO, VCF, VCA, Envelope Generator, LFO, etc., but there were a few interesting points about these circuits. The inputs, outputs, control voltage specs (one volt-per-octave) and power requirements were all identical to the 100M system. In theory the Digisound kits could be incorporated into a System 100M rack without any problems and at a tenth of the cost of the Roland equivalents. I devised a cunning plan.

I began by getting two System 100M racks (a 191J and a 190) but only 4 Roland modules, a 112-Dual VCO, a 110-VCO+VCF+VCA, a 140- Dual Env+LFO, a 182-Analogue Sequencer and the 100M 4 octave keyboard (model 181). I then built a few Digisound kits and mounted them onto thick aluminium control panels that were cut to the same dimensions as the 100M modules. I couldn't get the same mini sliders that Roland use so I had to resort to regular pots, I then applied rub down lettering to label the controls and sockets. This mix 'n' match set-up worked perfectly and sounded great. Functionally the Digisound circuits differ from the Roland modules in a few of ways. The Digisound VCF has an extra VC input for the resonance control but lacks the sociably High Pass Filter on the Roland VCF. The Digisound envelope generator is extremely versatile and has VC inputs for each of the ADSR stages but doesn't have the additional Roland inverted output. The Digisound LFO has a wider range and four simultaneous waveform outputs, but no delay control as on the Roland module. The Digisound VCOs have the benefit of 6 simultaneous waveform outputs, but the range control was a variable pot rather than a switched knob, which made tuning a bit more difficult than on the Roland VCOs. The stability of the Digisound VCOs wasn't as good as the 100M VCOs (which are even more stable than the Roland System 700), but compared to previous circuits and kits I had built these were the business.

Over the next couple of years I built around a dozen more Digisound modules, VCOs, VCFs, Envelope Generators, Envelope Followers and Ring Modulators etc. and for some I even sprayed the front panels the same colour as the 100M modules to fool myself into thinking they were Roland (sad man).

Eventually I added three more Roland racks and five more Roland modules. Another 182-Analogue Sequencer, a 172-Phase/Delay, a 121-Dual VCF, a 130-Dual VCA and a 131-Mixer.

I've been using the same Roland System 100M/Digisound set-up for about fourteen years, on stage and in the studio. Although the system hasn't left the studio for about eight years and isn't likely to now and fingers crossed, none of the modules has ever given up on me. Some of the mini jack sockets and controls on both the Roland and Digisound modules are beginning to show their age which can make tuning the VCOs a little problematic, but they couldn't really be described as unstable, just touchy. Some of the LED indicators have died and the Roland DIN to DIN cables have a tendency to spontaneously self destruct but so far there has been nothing that couldn't be fixed. And the beauty of a modular system is that if one module did develop a problem I could just whip it out and fix it without the rest of the system coming to a standstill.

In 1990 I sold my clunky 181 keyboard with every intention of buying the 184 polyphonic 4 voice version, but I had so much trouble getting hold of one, or for that matter anything for the 100M, that I eventually gave up looking. Luckily I still had an ageing Roland SH101 that I occasionally used as a keyboard controller and for sequencing the system modules using it's built-in sequencer and arpeggiator. I modified it by adding a Roland style 6 pin DIN socket that connected it, via a lead, to the 100M rack. This socket supplied CV and gate signals to the 100M rack and in turn the rack fed power to the SH101. Sadly the keyboard on the SH101 recently decided to stop working and seems almost impossible to get fixed.

Sequencers I've used for controlling the System 100M are the Roland 104 Sequencer from the System 100, the Roland CSQ100 and 600 digital sequencers and for the last 11 years the MC8 MicroComposer and the TB303 BassLine both hooked up to a TR808.

Summing up I have to say that in my humble opinion the Roland 100M is about as versatile, expandable and affordable a 'system' as you can get without getting your hands 'dirty' by going the DIY route. However, building your own modules is a great way of expanding a system. Also a point worth considering, if your not swayed by the idea of using a modular synth, is it has a genuine WYSIWYG interface, not a menu or hidden page in sight. If you have the space and the cash you can build any sort of combination that you could imagine. And believe me there are some pretty big 100M systems out there. I I've seen some of them, we're talking 8 racks/40 modules, the stuff dreams are made of. Well, I suppose I'll just have to keep buying those lottery tickets.

Roland produced 13 different modules and 3 keyboards for the System 100M between 1978 and 1985, although they had plans for at least 5 more modules, (see below). Before I explain the particulars of each module I will briefly cover some points about the system as a whole.

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 in a rack have their first CV modulation slider wired to the keyboard CV buss. The Envelope Generators also take their gate and trigger signals from the keyboard gate and trigger busses and all LFOs have their sociably phase sync wired to the trigger buss. All of these connections can be overridden by inserting a mini jack plug into the modules relevant sockets.

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 (overriding the keyboard) then they are fed through the rack's internal buss system. By linking more racks with the rear 6 pin DIN sockets a lot of unnecessary patching from rack to rack can be eliminated. However the front and rear 6 pin DIN sockets aren't exactly the same as each other. The front version carries CV, gate, trigger and two power lines, while the rear version omits the power connections. This allows the 100M rear 6 pin DIN sockets to be directly connected to the Roland System 700 buss socket and to either of the MC8 MicroComposer's 6 pin DIN CV/gate output sockets.

For those of you new to the System 100M here is a description of each module produced with it's original 1985 list price:

110 VCO/VCF/VCA £210
This module contains all the elements needed to produce a single synth voice. A few features are missing but that is to be expected when squeezing so much into a space only 4"x9". The audio signal paths for the VCO to VCF to VCA are all made internally as is the keyboard and envelope generator inputs to the VCF and VCA. All these connections can be overridden by inserting a jack plug into the relevant socket. The VCO has only one audio output, two VC inputs, no sync input and the PWM has only one control. The VCF has two audio inputs and two VC inputs. There are no LED's or HPF and the VCA has only two inputs and outputs and lacks a linear/exponential switch.

112 Dual x VCO £220
This module has two independent and identical VCOs. Each has a five position range control with settings from 32' to 2' and a fine tuning control. There are three modulation inputs, a sync input and output, with a weak/strong sync switch. Three waveforms are available, Triangle, Sawtooth and Pulse) but can only be output individually , via a switch, through two linked jack sockets. Pulse Width Modulation is available with a manual slider and an external VC modulation slider. These VCOs are pretty stable and have a very wide range and can be used as LFOs at their lowest end. If they are cross-synced at their higher ranges they make a nice impersonation of FM synthesis.

121 Dual x VCF £190
Each VCF is a -24 dB/oct low-pass type with a range of 25 Hz-20 kHz and a built-in fixed high pass filter that's sociably between three frequencies (1k, 2k and 5k). There are three audio and three control inputs. There are two linked audio output jacks with green and red LED's to indicate normal or overload output levels. Each VCF has a cut-off frequency slider and a resonance slider that can send each VCF into oscillation, enabling them to be used as sine wave VCOs. With a beautiful high end and a gut rumbling low end these VCFs sound incredibly rich and musical compared to most digitally generated filters nowadays. A good trick is to use two in series, each set to different cut-off frequency for an even deeper effect.

130 Dual x VCA £175
For each VCA there are three audio and three control inputs and two linked audio output jacks with green and red LED's to monitor output levels. They can be switched between linear and exponential modes for different amplitude curves and percussive effects when used with the envelope generator. Each has an initial gain control which also allows the VCAs can be used without a modulation input and as 3 channel audio mixers.

131 Output mixer/oscillator £175
This is a basic four input audio mixer with a level and pan control for each channel. There is master volume knob feeding three outputs, one mono and a left and right stereo pair, with each output having a single red overload LED. Additionally there is a separate stereo headphone output with it's own level control. Also included is a tuning oscillator covering 22 Hz, 440 Hz, 880 Hz, with it's own level control.

132 Dual 4 channel mixer £160
This useful module can be used for summing control voltages from various sources and/or for audio mixing. Each half includes four sliders for level, a simultaneous inverted output and a red overload LED. Included are separate sliders for providing variable positive and negative voltage sources.

140 Dual envelope & LFO £180
Both envelope generators have four adjustment sliders, Attack (1. 5 ms-7. 5s), Decay (4 ms - 15 s), Sustain (0-10v) and Release (4 ms - 15 s). There are three control outputs, two are normal linked outputs, the third is a simultaneous inverted output. On each EG is a switch to select an internal gate+trigger, gate only, or an external trigger pulse. A small push button can be used to activate each EG manually. The single LFO has five selectable waveforms, sine, triangle, square, ramp and sawtooth. The two linked LFO outputs can switched between x 1/10 and x1 levels. The frequency control, with range switch and an LED speed indicator (0. 05 Hz to 30 Hz), also has a CV modulation input. There is a delay slider (0 to 7s) and a keyboard trigger switch to phase lock the LFO to keyboard playing. With just this module, the 110 module and a CV keyboard you have all the elements of a basic synthesiser.

 150 Ring Mod/Noise/S&H/LFO £180
This versatile module has four sections. The sample and hold section has two sliders, one for clock rate (with an LED to indicate the speed) and the other for lag time (like portamento). It also has a three way switch for selecting which CV signal is sampled, external input, LFO or noise. There is also an external clock input, an internal clock output and a single S&H output jack. The noise generator has no controls, but four outputs. Two linked white noise and two linked pink noise outputs. Similarly the Ring Modulator has no controls. It's inputs are internally wired to the noise generator and the LFO but they can be overridden, there is a single RM output. The LFO is identical to the 140 module. This module is great for making 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 controllers. Each has a CV input (e.g. a keyboard) a CV output (e.g. to a VCO) and a portamento on/off switch, with green LED indicator. There is a slider for adjusting the the portamento time (2 ms to 5s) and a portamento modulation CV input. Also included is a MPX input (and red LED indicator) for switching the portamento on/off from an MC8 or MC4 MicroComposer, with a slider for setting the initial depth.

172 Audio delay/phaser/LFO/gate delay £210
This is another versatile module. The LFO has a frequency control with an LED rate indicator and it produces a triangle waveform to normal and inverted outputs simultaneously. At it's slowest 0. 04 Hz speed the LFO produces a maximum output of 10v p-p, but at its fastest 10 Hz setting the output is only 400 mV p-p. Output A is internally wired to the phaser and audio delay VC modulation inputs, but this connection can be overridden. For a deeper effect at a faster rate the LFO output from a 140 or 150 module should be used as they produce a constant 10v p-p output. The phaser section has audio input and output jacks and a CV input. There are three controls, a Modulation Intensity knob for adjusting either the internal LFO depth or an external CV input. A Shift Frequency knob varies the overall phase shift effect and finally there is a Resonance control. The audio delay (flanger) also has single audio input and output jacks and a CV input. The controls are Modulation Intensity (as above), Delay Time (0. 3 ms - 7 ms, this can be increased with an external VC signal) and Resonance control. Both the phaser and flanger have an effects on/off switch but neither has a mix control. Finally we have the gate delay. This section can accept most types of signal e.g. audio, gate or trigger pulses within a frequency range of DC - 2 kHz. The triggering threshold is 50 mV - 2 V . It will reshape and output the signal as a 0-15V gate. A delay of 0. 3 ms - 6 s and a width of 0. 3 ms - 6 s can be applied to the gate. There are three knobs, threshold, delay time and gate time. There is also a gate output LED and an input and output jack.

173 Signal gate & multiple jacks £125
This module has no knobs or controls just sockets, 28 of them. There are four electronic switches each with a frequency response of DC to 20 kHz and S/N of over 100 dB, pretty good. Each switch has signal in and out sockets (for audio or VC), normal and inverted gate inputs (for switching the signal on/off) and a red LED indicator. Below these four signal gates are six banks of four connected sockets for linking complex patches.

174 Parametric EQ £155
This is a single channel, four band parametric equaliser with a S/N of 90 dB. The four bands are : 1) 20 Hz - 200 Hz 2) 100 Hz - 1 kHz 3) 500 Hz - 5 kHz 4) 2 kHz - 20 kHz

Each band has a slider for tuning the bandwidth and a slider for cutting or boosting the level by 12 dB. The module has a single audio input and two linked output sockets. There is an EQ bypass switch and green and red LED's for indicating normal or overload output level.

182 Analogue sequencer £200
This nifty little sequencer can be used in a parallel two channel eight step mode, or in a single channel 16 step series mode. There are 16 tuning knobs and a tempo control (0. 14 Hz - 33 Hz) with a tempo CV input. The step number control sets the length of the sequence and the step switch allows the sequencer to repeat, step (from the trigger input) or play once and stop (which initiates the end pulse). There is a portamento control (0-10s), a start/stop button, a parallel/series switch and 8 step indicating LED's. The gate time control feeds a gate output socket (10% 90%/ 15V), there is also an end pulse output jack (10 ms/15V). There are CV output jacks and range switches (3V or 10V) for each channel. The sequencer trigger input will accept a 5V-15V gate (1 ms minimum). The end pulse can trigger a second sequencer to create longer sequence steps or the gate output can step a second sequencer in parallel.

180 32 key controller keyboard £210
This is the most basic System 100M keyboard with only a tuning knob, a portamento knob and a three position transpose switch. There are three outputs CV, gate and trigger. These are available as mini or standard size jack sockets. Finally there is a 6 pin DIN socket for directly connecting to the keyboard to the 100M rack.

181 49 key controller keyboard £275
Apart from an extra 17 keys and some additional features this model has the same clunky keyboard action as it's smaller brother. Also included are a centre sprung bender control, bender output jack sockets and a portamento on/off switch.

184 4 note polyphonic keyboard £490
This is the largest and most specified of the 100M keyboards. Although there are the same number of keys as the 181 the action is definitely an improvement on the other models. It has all the features of the 181 keyboard except for the 6 pin DIN socket and it does have a number of useful additions. There is an arpeggiator with a rate control and four push buttons for selecting Up, Down, Up&Down or Random modes. Plus an arpeggiator clock input on the rear for connecting to a drum machine or sequencer trigger output. There are 4 assign mode buttons for selecting two Unison (monophonic) modes and two Poly (4 voice) modes of playing. Next to these buttons is a hold (sustain) switch. The bender also has a pitch bend sensitivity knob, which should be at 0 when playing the keyboard. The transpose switch only has two positions on this model, normal and 1 octave down. Along the rear of the keyboard are 4 CV and 5 gate outputs. The fifth gate socket is a combined output of gates 1-4. and all the outputs are available as mini and standard jack sockets.

190 Rack for 3 modules £155
191J Rack for 5 modules £230

When originally sold, the racks came as flat pack self-assembly units. They consist of two wooden end-cheeks, a steel top and a heavy steel base containing the power supply and all the connectors. A 191J containing all 5 modules weighs about 16 kg, pretty heavy. The only differences between the two racks are the number of modules they can accept and the front panel 33 jack, 9 bank patch bay on the 191J.

Next to the front 6 pin DIN socket are six mini jacks allowing CV, gate and trigger signals to be input or output. Next to the front patch panel are two pairs of A-B sockets (mini and standard size, linked) that are connected to two phono sockets at the rear. The A-B phono sockets on the rear of the 191J and the 190 often get overlooked but they can be very useful for linking signals to other racks and saving on patch cords. Finally there is an on/off switch and power LED.

Until a couple of years ago there was a regular market for second hand Roland 100M systems. Every few months another one (or part of one) would appear in the classified ads of some music mag or other. But for about a year or so the only systems I have seen for sale were by shops or specialist retro dealers. And for that privilege you usually pay a hefty premium. People just seem to be hanging on to them.

However all is not lost if you live in an area with regular boot sales, jumble sales and lots of junk shops. I occasionally hear about single modules being discovered in the most unlikely place and for ridiculous prices. How about a Roland 150 module (RM/Noise/S+H etc. ) for a tenner, sold to the man at the back! Yep true, at a boot sale last year. The guy selling it had absolutely no idea what it was, let alone how much it was worth. And I've heard similar stories about incredible finds in old music shops. But why does it never happen to me? Last year, in Belgium I came across a 172 module (phaser/audio delay) just sellotaped into a cardboard box and looking the worst for wear. As soon as I showed an interest in it the guy decided it was worth £250. Get lost chum!

But seriously, keep your eyes peeled you never know what could be under that pile of old plates and socks.




There is a little known ring modulator effect called 'bowing' that I first came across in the 1970's. 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 audible until the the voltage source begins moving, similar to a VCA. The difference is that the output level varies with the speed of change not the level of the voltage. Adding a VCF to the output of the RM and using different combinations of audio and CV sources for the RM then unusual 'bowing' and 'blown' effects can be achieved. Alternatively it could come in handy as a substitute VCA.

 LFO as EG
If you are sequencing with the 182 module and running short of Envelope Generators then a substitute EG can be found lurking in the 100M LFO. One of the keys to this trick is matching the sequencer and LFO speeds e.g. if the sequencer rate is 6 then also set the LFO rate to 6. Plug the sequencer gate output into the keyboard trigger input, on the rack front panel , 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 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 envelope generator. By setting the LFO rate slightly higher than the sequencer rate you can also achieve some nice poly rhythmic effects.

If you have a particularly complex patch set-up that you would like to reuse one day, then it's often impractical to make notes of every connection and setting. A much quicker and more reliable solution is to take a a series of photo's of the set-up. Making sure that everything is sharp and well lit, it is even possible to use a something like Polaroid.

When working on new patches it's surprising how many good sounds and effects you keep coming across. But I often find that I just keep on adjusting and re-patching hoping to refine the sound a little bit more. Before you realise it you've lost that fab sound you had 10 minutes ago and now you've forgotten how you did it. Well if you have a DAT machine and a sampler then it's worth connecting up the DAT to your mixer before you start programming patches. Load it with a 2 hour tape and keep the DAT machine remote control nearby and when you start programming hit record. As you carry on working you can shoot index points at your DAT machine every time you do something that sounds good. Afterwards you can go back to the index points on the tape and sample them. Not an ideal solution, but at least you have something to show for all that knob twiddling.

While we are on the subject of sampling it's often said that it's just not the same when you sample analogue gear. Well it probably isn't but a lot of people (and a lot of sample CD's) get it wrong by sampling individual notes, even multi sampling individual notes doesn't always sound right. One of the things that make analogue sound so good is the movement and fluctuations in the sound. You only really hear this 'feel' over a period of time. I've found that the best way to capture a more authentic analogue feeling is to sample whole bars of sequences and keyboard parts. If you have the sample memory then it's worth trying at least 2 whole bars (the more the better) and also sampling subtly different versions of the same sequence or keyboard part. Then try alternating each one when you play them back.

If you want to go all the way then you could try running your original analogue sequences alongside you sampled versions for some really rich tones.

System 100M modules (if you can find them) can accept very high level audio signals (10v-15v p-p) and have a very wide frequency response. The 121 dual VCF and 172 phaser+flanger modules, in particular are great for processing keyboards, pro studio gear and using on mixer inserts. And if you can find a 110 VCO/VCF/VCA module then you've almost got a complete analogue synth in shoe box.

OK, you manage to get hold of a module but you don't have a rack to power it. Or maybe you have one too many modules for your rack. If you can handle a soldering iron and it's just a single module, then something like the Maplin +/- 15v (100 ma) PSU should fit the job (part no. LP88V & XX04E, catalogue page 255). You need to make up a lead with an 8 pin DIN plug at one end to supply the module (part no. FJ91Y, page 505).

Warning: please 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 by an incorrectly wired plug or PSU. Mistakes can be expensive.

System 100M 8 pin DIN plug connections are as follows:
Pin 1 PSU/plus 15 volts
Pin 2 gate
Pin 3 no pin
Pin 4 LED +
Pin 5 trigger
Pin 6 PSU/minus 15 volts
Pin 7 PSU/ground
Pin 8 CV
Pin 9 LED ground
These connections are also relevant if you wish to make your own replacement 8 pin DIN to DIN leads.

While we're on the subject here are the pin connections for making your own:

6 pin DIN to DIN leads for linking 100M racks to other racks or keyboards etc. (6 pin DIN plug, Maplin part no. HH29G, page 505). If you are linking racks then you can leave pins 1 and 2 disconnected. But if you are connecting a 100M keyboard then use all pins.
Pin 1 PSU/minus 15 volts
Pin 2 PSU/plus 15 volts
Pin 3 gate
Pin 4 trigger
Pin 5 PSU/ground
Pin 6 CV

It's relatively easy to interface the 100M with other Roland and non-Roland analogue synth gear. For keyboards, most manufacturers use the 1 volt-per-octave control voltage standard and a positive going gate pulse (ground to 5-15v). The major exceptions to this rule are Moog , who use an 'S-trigger' gate pulse, which is a shorting connection (pulse to ground) and Yamaha, who use a negative going gate pulse (+10v to ground). Korg on the other hand use a negative going gate pulse (+5v to ground) to trigger their EGs and a positive going gate pulse (ground to +5v) to initiate EG release. However some Korg instruments use the Moog type 'S-trigger'. Korg also use an incompatible Hertz to Voltage system of keyboard control. Korg used to produce the excellent MS-02 interface which could convert gates and control voltages between standards, in either direction.

If you don't have access to such a unit then the gate delay section of the 172 module and the inverting mixer outputs of the 132 Voltage Processor module can sometimes be combined and/or tweaked to get a decent gate signal from some incompatible sources. The 172 module is also brilliant at converting audio signals into gate pulses. If used with the 174 EQ module it's possible to isolate a percussion sound on a tape, a bass drum say, and convert it to a gate pulse for triggering an envelope generator or stepping a sequencer.

Here is a list of various manufactures gate/trigger specifications:
Roland equipment will trigger from a 5-15v (20 ms min. ) positive gate pulse and most Roland drum machines and analogue keyboards etc. have a 10-15v positive going gate pulse output.
ARP gate pulse ins and outs are: 8-10v gnd to positive.
EMS gate pulse ins and outs are: 4v gnd to positive.
PPG gate pulse ins and outs are: 15v gnd to positive.
PPG gate pulse ins and outs are: 15v gnd to positive.
Oberheim gate pulse ins and outs are: 9-15v gnd to positive.
Prophet gate pulse ins and outs are: 15v gnd to positive.
EDP (Wasp/Spider sequencer) gate pulse outputs: 'S-Trig' and 9v gnd to positive.
Yamaha gate pulse ins and outs are: 10v negative to gnd.
Korg gate pulse ins and outs are: 5v neg/5v pos to gnd and sometimes 'S-Trig'.
Moog gate pulse ins and outs are: 'S-trigger' (shorting connection)

Apart from using one of the Roland 182 sequencer modules there are many ways of controlling the System 100M. As I mentioned before, The Roland MC8 with it's 22 outputs is ideally suited as is the MC4 with 16 outputs, both have their strengths and weaknesses. And even though the Roland MC202 only has a single CV and gate output it is also worth considering. The Roland TR808 Rhythm Composer with it's 3 trigger pulse outputs can be used to step the 182 sequencer and a couple of envelope generators, or even a second or third sequencer module. Be warned though, using 'digital' CV sequencers will seem pretty hard going compared to MIDI. But that is the nature of them, they still get the job done, it's just accomplished differently.

I know there are purists who run screaming at the mention of the M word and I have tried to put off mentioning it at all, but I'm afraid we live in the real world and there's no way it can be avoided any longer. Traditionalist won't agree with me, but I actually think it's quite desirable to integrate old analogue synths into MIDI set-ups. With the proliferation of MIDI to CV converters available, from cheap single channel units to sophisticated multi channel types, it has never been easier. Newer models like the Kenton Pro-4 offer MIDI to four channels of CV, Gate, Trigger, Portamento, Pitch Bend and Modulation etc. and are ideally suited to systems like the Roland 100M.

An alternative, but less sophisticated route is to use one of the Roland TR 626, 707, 727 or 909 Rhythm Composers. All have a MIDI input and all have a trigger pulse output that could be used for stepping the 182 module sequencer or triggering a 100M Envelope Generator.

I use a small Groove three channel MIDI to CV converter that can control two 100M voices and my Wasp synth. At the moment I'm using a MIDI keyboard as a controller for my System 100M, but it isn't quite the same as using a proper CV keyboard.

Famous and Infamous System 100M Users:
Throbbing Gristle
Chris & Cosey
Human League
Depeche Mode
Heaven 17
Martin Rushent
Hans Zimmer
Nitzer Ebb
And many more

Looking through old Roland catalogues, manuals and press releases I uncovered various references to System 100M modules that, as far as I know, never made it past the drawing board. They were sometimes listed under the heading 'PLAN'. 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 (DCB? or MIDI?)
170 Pitch to Voltage converter/Envelope Follower/Amp

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 (Indicator)
PSU Power Supply Unit
DIN Small multi pin connector
p-p Peak to Peak
S/N Signal to Noise ratio
dB Decibels
DC Direct Current
V Volts
ms Milliseconds
Hz/kHz Hertz and Kilo Hertz, number of vibrations per second
EQ Equaliser
EMS UK Synth manufacturer
ARP US Synth manufacturer

Copyright © 1995 Chris Carter / SOS Publications.
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