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EMS VCS3 [Retrozone]

Analogue Synthesizer By Ian Boddy
Published January 1994

EMS VCS3 synthesizer.EMS VCS3 synthesizer.

Synthesist Ian Boddy steps back in time to report on this classic British sound machine, regularly found haunting the electronic music departments of many a university, and a recent addition to the author's own sonic armoury.

A couple of months ago I walked into a music shop and saw a synth I just had to have. What was this machine of my dreams? The latest all‑singing, all‑dancing digital workstation? Nope... it was, in fact, a VCS3. A "VCS what?" I hear many of you mutter. Well, for those of you who have never before seen one of these wonderful instruments, the VCS3 was the first portable synth ever made and could well be classified as an antique of the synthesizer world, having first seen the light of day way back in 1969. This means that the beauty I picked up may well be older than many of you reading this article. "Gosh!" some of you cry, "but doesn't that mean that it's going to sound rubbish? After all, it's not going to have MIDI, there's no presets, it's only monophonic, it won't stay in tune, etc..."

Well, actually, no. If anything, these apparently negative attributes contribute a lot to the machine's character — and believe me, this synth has bags of character! It may be no good at trying to emulate the standard sounds found on all modern day synths — strings, pianos, brass, guitars, yawn, yawn — but it can produce some truly gut‑wrenching sonic effects. We're talking here about sounds that can take off the top of your head; noises that can make all your fillings jump and your teeth itch, and effects that make you say "what the hell was that?". Of course, these type of noises may not be to everyone's taste, but the point I'm trying to make is that the VCS3 can produce sounds that none of the modern day synths can make and as such it can give your music a true degree of individuality; something that is becoming more and more difficult to achieve with the current generation of PCM sample‑based keyboards.

What's With The Knobs?

The first impression you have on encountering a VCS3 is that it looks more like a piece of physics laboratory test equipment than a musical instrument. It is basically an L‑shaped box with wooden sides, the vertical part being bedecked with numerous potentiometers ('knobs' to you and me) and the flat part being dominated on the left by a patch‑pin matrix board and on the right by a joystick. There is a variation on the VCS theme in the shape of the AKS, which is basically the same machine but squashed into a black plastic suitcase.

The VCS3 can be thought of as a modular synth, but unlike most of its contemporaries which used a patchcord system to connect the various synthesizer modules together (and thus ended up resembling huge telephone exchanges festooned with bundles of spaghetti‑like wires), a much more compact patch‑pin matrix board was employed. This is basically a 16 x 16 way pinboard, about 10cm square. By inserting a patch‑pin into the relevant hole, it is possible to connect any output (horizontal row) with any input (vertical row). These pins replace the patchcords mentioned above and thus provide a much more convenient way of interconnecting the components of the VCS3.

Sound Sources

Let's take a brief tour of the sonic armoury the VCS3 provides...

The main sound sources are three voltage controlled oscillators (VCOs) and a white noise generator, although the voltage controlled filter (VCF) can go into self‑oscillation to provide an additional pure sine tone. The frequency of each of these VCOs is controlled by a pot that is calibrated numerically from 0 to 10, instead of the more familiar musical measurement of feet (or octaves). Thus all three VCOs have to be tuned by hand and ear, making the humble tuning fork an essential accessory when trying to get the machine to stay in tune. However, the frequency range of these oscillators is truly immense: VCOs 1 and 2 extend from about 0.6Hz to 16.7kHz; VCO3 from about 0.015Hz to 500Hz. This means that all three VCOs can be used as low frequency oscillators (LFOs), if required, although VCO3 tends to take on the LFO duties more often than not, because of its incredible bottom frequency (it has a time period of 65 seconds!).

Various sine and ramp waveforms are available with VCO1, whereas VCOs 2 and 3 generate square and triangle shapes. To provide even more variety, all three VCOs have a Shape control which can modify the basic waveform into, say, a pulse shape from the square wave and a negative or positive sloped ramp wave from the triangle wave. Thus these three basic VCOs can cover a huge range of frequencies and waveforms, and can perform as either audio or low frequency oscillators.

The VCS3's white noise generator consists of a Level control and a Colour control. This latter function can be used to emphasise either the bass region or top end of the basic white noise source and is useful for creating a more rumbly effect in the former case or a thinner, more hissy sound in the latter.

Lastly, the voltage controlled filter can be induced into self‑oscillation. This produces an ear‑splittingly pure sine wave, the frequency of which can be tuned using the filter's cutoff control.

Sound Treatments

The voltage controlled filter (VCF) is a simple low‑pass type with a cutoff rate of 12dB for the first octave and of 18dB per octave thereafter. It simply consists of three controls: Frequency, Response (often called Q) and Level.

To the left of the VCF controls is a single knob controlling the level of the ring modulator. This sound treatment, more than any other, gives the VCS3 its characteristic sound. A ring modulator is a device into which you feed two signals, the frequencies of which are added together and subtracted to provide two new frequencies at the output (the original two input signals are not heard at all). Ring modulation on the VCS3 is particularly good at producing clangorous bell‑like tones (akin to the DX7), which is often due to the fact that although the two incoming signals may be musically related, once their addition and subtraction frequencies are presented they most definitely aren't. The more harmonically complex the two input waveforms, the greater the degree of enharmonic 'harshness' of the output. A particularly nice effect achievable with a ring modulator is when one of the input signals is swept in pitch. This produces two different signals at the output, one rising in pitch and the other falling.

Next up is the envelope shaper, which is very crude when compared with modern day multi‑stage envelopes but can nevertheless provide quite a high degree of control. There are controls for Attack, On (sustain) and Decay time, as well as a knob entitled 'Off' which actually has the effect of retriggering the envelope automatically (it can also be triggered manually via an Attack pushbutton). A Level dial is also provided along with a Trapezoid control, but more on these later...

Next in line we have the onboard effects. "Wow!" you exclaim. "Built‑in effects on a synth this old?" Well, actually, it amounts to a dual line spring reverb which can do little more than go 'boing', but can, if used judiciously, have a charm of its own. The controls available for this splendid device are Level and Mix (which balances the 'dry' and 'wet' signals).

Lastly there are two output filter controls (one for each channel). These are simple tone controls, giving a small degree of overall treble/bass cut or boost.

Sound Controls

Several elements of the various sound sources and treatments discussed above can be voltage controlled on the VCS3. Firstly, and probably most importantly, there are the three VCO frequencies (although it is possible to have a modification done which also allows control over the waveform shape). The decay time of the envelope shaper can be varied, as can the Mix control of the reverb. The filter cutoff point can be modulated and the output level of the two channels can be individually controlled. The Trapezoid function mentioned earlier is, in effect, a control voltage (CV) source that mimics the shape set up on the envelope and can be patched to any destination you like.

Apart from all the manual knob‑twiddling that can occur on one of these machines, another source of control is the joystick. This can have variable vertical and horizontal ranges (thus enabling very small to very large changes), the actual shape that the stick traverses being a square; this allows two separate elements to be manipulated simultaneously.

Outs And Ins

The VCS3 is a two‑channel machine, permitting either a stereo sound to be set up or two independent tones. Quite naturally, therefore, there are two independent Volume and Pan controls for these two channels, and these are located on the bottom right of the flat part of the front panel. Two input channels are also provided, which can be patched into the matrix board, the level of these signals being controlled by a further two knobs. When an external keyboard is used, such as the EMS DK2, the amount of voltage control being sent to the VCO frequencies is controlled via these pots. The significance of this is that there is no pre‑configured octave tuning from the keyboard. In other words, as well as having to individually tune the pitch of each of the VCOs, it is also necessary to tune the octave span using one of these controls. This, as you can imagine, can sometimes be a little tricky and quite alien to anyone brought up on modern synths. The plus side, however, is that it is possible to set up all sorts of wild and wacky macro‑ and micro‑tuning scales.

Looking around the back of the machine, apart from the mains lead socket and fuse holder, we find the following ins and outs: a stereo headphone socket; two signal outputs as well as two control voltage outputs (used for controlling external devices); two hi‑level inputs, which can accept either an audio signal or an external voltage source; two microphone inputs. In addition, there is a strange 8‑pin socket (apparently called a Jones connector) into which the DK2 keyboard can be plugged. This gives direct keyboard access to the triggering of the envelope, with the pitch of the VCOs being controlled by patching in one of the input channels on the matrix board. (It is possible to get the VCS3 under MIDI control via a MIDI‑to‑CV convertor. It requires a simple mod to the Jones socket, so that the gate input feeds into one of the control output jacks with the CV input entering via one of the hi‑level inputs.

The last socket is an output from the meter and is marked 'scope'. This allows a signal to be sent from the VCS3 to an external oscilloscope for monitoring purposes. The meter is located at the bottom right of the vertical front panel and can be used either to monitor control voltages or signal levels. It is quite useful in checking various levels when they are critical to the success of a patch. Any sound source can be patched into the oscilloscope, via the matrix board, and then taken out of the Scope socket as mentioned. Interestingly, if this signal is then patched back into one of the hi‑level inputs a useful side‑effect occurs. This is due to the fact that the input amplifiers invert any signal presented to them. Thus it is possible to obtain an inverted control voltage source, which can be repatched into the matrix board.

Patching It All Together

Close-up of the patch matrix on a EMS VCS3.Close-up of the patch matrix on a EMS VCS3.This is where the fun really starts. When creating a sound on the VCS3 one builds it up step by step, by connecting a row with a column on the matrix patch board by means of a patch‑pin. This leads to a very logical way of working which, in many ways, is second to none in teaching the user the basics of synthesis. This has led the machine to become very popular with educational establishments and, indeed, many of the VCS3s currently in use can be found in colleges and arts centres throughout the country. Many of the principles involved are just as relevant today as they've always been.

The great thing about creating a sound on a VCS3 is that you have to build it up step by step; there are no memories and thus no presets. This gives you the chance to examine each element of a sound 'patch', rather than being presented with a near‑complete article as is so often the case with modern day synths. The process involved goes something like this. Oscillator 1 (row 1) is connected to the filter (column H). The filter output then appears on row 10, which you can then connect to the envelope shaper on column D. The envelope output on row 12 could then be linked to the output channel 1 column. Some modulation control from VCO3's square wave (row 5) may then be required to vary the pitch of VCO1 (column I)... and so on.

Of course the above example is a very simple patch and if you keep going you can end up with a much more complex sound involving perhaps 20 to 30 patch‑pins. Things can then start to get a little bit tricky, especially in a live performance situation when one of your pins drops on the floor and rolls out of sight! If this all sounds very complicated, believe me it's not; you soon become accustomed to the logic of the machine. Once you do, you can then in fact throw logic out of the window and start connecting anything to everything else. There are literally no rules here. If you want to connect the output of VCO1 to control its own frequency — fine! If you fancy ring modulating the ring modulator's own output, or even routing the output of the filter to control the pitch of a VCO (even though that VCO is already patched into the filter), then no problem. This, in essence, is why the EMS VCS3 is such a versatile sound generator and why it is often possible to create such extreme sounds. Just sit down, pick up some pins and begin patching them in. As the sound begins to form you may pursue a logical path that you have predetermined, or you may just want to patch any old thing together and just see what happens.

OK, so there are problems in keeping the infernal machine in tune, and you're never going to get stunning string or piano sounds out of it, but that is missing the point. We're looking at a classic analogue synth here that can produce sounds which none of the modern brigade of keyboards can match. Sounds that are as relevant today as they've ever been; indeed it could be argued more so, bearing in mind the recent 'back to analogue' trend in dance‑related music. The VCS3 is an instrument that can be very rewarding to use, despite (if not because of) its many idiosyncracies. There's not a lot of them about on the secondhand market, but if you ever get the chance to have a play on one, then get stuck in there and give that joystick hell!

EMS: A Brief History

EMS (Electronic Music Studios), the British company that designed and built the VCS3, was the brainchild of one Dr. Peter Zinovieff, who established an experimental synthesizer studio in the 1960s in Putney, South London. The services of designer David Cockerell were engaged to help produce a computer‑controlled music system and, by 1968, the fruits of their labour resulted in a system which was capable of storing and transforming any analysed waveform and playing it back through a network of 60 sine wave oscillators. (As a point of interest, David Cockerell was also behind the designs of Akai's S1000 range of samplers.) However, due to the ever‑increasing financial demands of keeping such a studio open, a decision was made in the late 1960s to produce a commercial synthesizer and in November 1969 the VCS3 (Voltage Controlled Studio No.3) became the company's first product.

Over the next few years EMS came out with several innovative devices, including the world's first multitrack sequencer, pitch‑to‑voltage converter, velocity sensitive electronic keyboard, and commercially available vocoders. By the mid '70s the VCS3 (and its little brother, the suitcase‑bound model AKS) had become something of a classic and was used by many famous bands like Pink Floyd (check out the pulsating sounds of 'On The Run' from Dark Side Of The Moon), Yes, Tangerine Dream, Hawkwind and The Who to name but a few. However, its most famous exponent must surely have been Brian Eno in his days with Roxy Music (he appeared with them on BBC TV's Top Of The Pops, resplendent in glitter suit and feather boa, madly whirling the VCS3's joystick).

In the second half of the '70s, the arrival of programmable polyphonic synths from American and Japanese companies threatened to eclipse the merits of the highly versatile VCS3. EMS's answer was to design the Polysynthi. Unfortunately, this was a commercial flop (only 50 were ever made) and eventually the company was forced into insolvency in 1979. However, the spirit of EMS refused to die and the rights to all the products were bought up by a company called Datanomics in Dorset. The sales were handled by Robin Wood, who had originally joined EMS as a demonstrator in 1970. After a further five years though, the legacy of EMS was on the move once more, this time being bought up by composer Edward Williams and today we find the company operating from Truro in Cornwall.

The VCS3 is no longer in production, although reconditioned machines can occasionally be obtained for about £700‑£800. The current list of EMS products includes the excellent Vocoder 2000 and the innovative Soundbeam system (an ultrasonic distance‑to‑MIDI converter, which allows body movements to control any MIDI device). It's good to see that this once innovative British company has managed to survive in this world of mass‑marketed instruments and that it is in the good hands of Robin Wood, who exudes such enthusiasm about both the current range of products and the trusty old VCS3s that still survive.