The following article contains an interesting synthesizer survey in 1972, published in the Studio Sound magazine

Obviously not a lot of different synthesizer brands were available at the time. Although we believe that this survey is not complete (at all), it is very interesting to read about the different systems and their capabilities.. Especially the ARP 2600, the EMS synthi and modular Moog systems. And if you read carefully you will see some quite rare synths as well.

The full text is below the images.

Rightly or wrongly, R. A. Moog is generally credited with the onginal development of the voltage controlled mus ic synthesiser.

Certainly he was the first to manufacture synthesisers on a commercial scale. His problem was to produce a link between the natural Jaws of electronics and the conventions of music. Voltage control was at t at time, just a few years ago, one of various techniques employed by pioneer electronic music composers.

Moog recognised it as a versatile means of automating an infinitely versatile yet highly labour intensive art form. A vc synthesiser comprises, in one cabinet, many of the electronic tools formerly available (if at all) only as separate units. Moog offered more than compactness: the ergonomic convenience of an integrated synthesiser compared with a scattered array of physica1ly and electronically ill matched components.

That at least was the theory. In practice, the Moog system suffered from the same failing that beset the casua1ly assembIed equipment it was trying to replace. Routeing between modules was (and still is) by jack patch cords, raising difficulties if an operator wished to connect one output to a large number of inputs or vice versa. An addi tional problem with patch cords is their tendency to obscure the jack field which in Moog equipment is the con trol face itself. Despite this, the Moog name is as firmly established among musicians as the name Hoover among housewives.

The fact that Moog is really pronounced Moge, Moag or Mogue is neither here nor there. Another American manufacturer, Tonus Incorporated (pronounced ARP) found a tidier and more versati1e altemative to patch cords, in the shape of 20 position switch rows. The ARP 2500 using this principle is field tested on page 39. Another ARP, another routing system: the smaller 2600 combines Moog-style input/output jack sockets (miniature in this case) with internally wired module conoections made by opening slide faders. The trouble with prewiring is that it can impress preconceived notions on the performer’s mind, severely rest ncting tonal variety.

Tbe most logical, physically convenient and versati1e method of routeing synthesiser modules is the pin matrix system employed by Elect ronic Music Studios (London) Ltd. This company produces two basic synthesisers, the smallest being variants of tbe VCS3 with a 16′ matrix. Largest is the Synthi 100, incorporating two 60′ matrices. The connections of one output to 60 inputs through a 60 2 matrix would take one or two minutes; the time needed to insert 60 patch pins along one output row.

The same task using patch cords could take an bom’s soldering, unless you were fortunate enough to possess a one-to-60 way patch lead. The ARP 20 way switch bank comes unstuck if you wish to route more than 20 inputs independently to 20 outputs. Patcbing one switch bank to another in the 2500 ralses this limit to 40, still less than the capacity of a pin matrix which normally equals the number of signal outputs. As synthesizers grow more complex, these practical operational factors will acquire major importance. The pin matrix must inevitably become a standard, as will another EMS innovation: the digital sequencer. Preparing a sequence by individually tuning presets (the facility offered by Tonus and Moog) is crude and inefficient. The Synthi 100 sequencer can be programmed direct from a keyboard and stores up to 256 events in six sin1Ultaneous parameters.

Two companies, Dewtron and Chadacre, have recently started producing individual voltage control modules. Chadacre are the first mixer manufacturer to enter the synthesizer market. They will undoubtedly be followed by others, with the li kely effect th at voltage control techniques will start to appear in studio mixing desks. Tbe Chambers Dictionary definition of synthesis is ‘building up, putting together, making a whole out of parts’; syn/he/ic as ‘artificiaJly produced but of like nature with, not a mere substitute for, the natural product’; and syn/hesise as a faulty form for syn/hetise. Whichever way you read it, the synthesiser/synthesizer/synthetiser is no more artificial than a saxophone.

The one produces sound from vibrating electroncs, the other from a vibrating reed, the harpsichord from vibrating strings, the glass harmonica [rom vibrating glass and the aeolian harp from vibrating air currents. Artificiality only arises when electronic means are employed to imitate non-electronic instruments. At the present state of the art, sucb exercises are neither convÎncing nor profitable.

A no violin can produce vastly more complex wave structures than the largest electronic synthesiser so if you need a violin, lIse a violin. If yOll desire effects unJike anything previously heard by man or beast, then use a synthesiser. But, for the love of music, avoid the trap which faces composers of electronic Pop: using a £7,500 synthesizer to imitate unconsciously but all too successfully a cheap divider organ. lt has been done and it degrades the most promising invention since the development of the chromatic keyboard.




Advance data only- Polyphonic keyboard synthesiser suitable for placing above an organ or piano. May also be used freestanding. Plug-in board ie circuitry. Keyboard Five octaves. Controls : Legato and attack keying, sustain on/oft and sustain duration. Keyboard balance, reverberation level, vibrato, light controlled expression pedal and earth disconnection switch. Output: High impedance (jack soeket) to external amplifier. Power: 115 to 240V, 50 to 60 Hz. Dimensions: 960 x 500 x 180 mm high. Price: To be announced.

MANUFACTURER: Audio Synthesisers Ltd, 14a Broadwalk, Pinner Road, North Harrow, Middlesex HA2 6AD.



6305 white noise generator. Two noise generators, two independent variabie bandpass filters and two phasing amplifiers. 45° facia, 200 x 150 x 150 mm dimensions. 20 transistor circuit with nine variab ie controls and two output jacks. Price: £49.50. 6303 oscillator. Square and saw outputs. 100 ka input impedance permits use of a capacitor sustain memory. 200 mV per octave control sensitivity.

Price: £15 6306 envelope shaper. Variabie attack, on, decay and oft times. Self-triggered. Price (including control potentiometers): £18 6307 white noise generator. Price: £10. 6301 integrated circuit ring modulator. Price: £15.50

MANUFACTURER: Chadacre Electronics Ltd, 43 Chadacre Avenue, Clayhall, IIford, Essex.



VCA-1 amplifier. Input impedances: 50 ka (signal) and 100 ka (control) . In put level: 500 mV maximum. Price: £ l0 PH-1 phasing module. Price: £17 SA-1 selective amplifier (vc filter). Price £12 AF-1 fader. Price: £9. VCO-1 oscillator. Produces 500 mV saw and 700 mV square waves to feed 20 ka and 10 ka loads respectively. Oscillation commences at 1 V con trol voltage, rising at 200 mV per octave. Square symmetry preset control facility. Price £9.50 (El discount for two or more VCO-l modules). Joystick control : £4.50. Patchboard sockets £7.50 per hundred. Patchboard plugs: 8p each (minimum of ten plugs).

MANUFACTURER: Design Engineering (Wokingham) Ltd, 254 Ringwood Road, Ferndown, Dorset.



Voltage controlled electronic music/sound-effects generator. Power requirement: 220 to 240V or 105 to 115V, 50 or 60 Hz. Battery operation possible. Internal sources: Oscillator 1 : 1 Hz to 10 kHz sine and ramp. Oscillator 2: 1 Hz to 10 kHz square and ramp. Oscillator 3: 0.05 Hz approx to 500 Hz square and ramp. Filter when set to self oscillate supplies variabie frequ ency sinewave. Trapezoid signal produ ced by envelope generator. Noise generator with amplitude and coloration controls. Internal treatments: Envelope (attack / decay generator), reverberation spring un it, band pass filter and ic transformerless ring modulator. Input sensitivities: Two 5 mV ac into 600 ohms, one ± 50fL A into 500 ohms; ± 2.5V dc or 1.8V ac into 50 kO.  Outputs: Two 10V into 50 ohms (headphones), two 2V into 600 ohms (Iine), and dc control output. Internal monitors: Side-facing loudspeakers driven by 1W amplifiers. Finish: Solid afrormosia cabinet. Slide-out bottom and rear panels. Plastic on heavy gauge aluminium, taking temporary wax pencil marks. Dimensions (hwd) : 438 x 444 x 419 mmo Weight: 10.2 kg.

Price: £300 (excluding keyboard).


Source Modules:

Three voltage controlled audio waveform generators: sine and ramp. A sine shaper is included by which variabie amounts of even harmonic distortion may be added. Manual frequency range: Greater than 1 Hz to 10 kHz (extendible by voltage controls in both directions to 0.25 Hz and 20 kHz). Three voltage controlled audio waveform generators: triangle and square. These can be varied from triangle to sawtooth ramp and from symmetrical square to short pulse, in either polarity. Manual frequency range: Greater than 1 Hz to 10 kHz. Triangle symmetry ± 5 per cent rise time to fall time equality. Other specifications as for sine/ramp oscillator.

Three voltage controlled low frequency waveform generators: Same details as before but oscillators are 20 times slower. Frequency range: Greater than 0.025 Hz (40 seconds per cycle) to 500 Hz. Voltage control: 500 mV/octave. All nine of the above oscillators have synchronisation inputs so that they can operate at an integral multiple of another oscillator.

Three noise generators: Variable from white (central position of coloration control) to dark or light positions (Iow or high pass filters). Distortion: In white position, frequency content is flat ± 3 dB from 100 Hz to 10 kHz.

Dual output random control voltage source.

Treatment modules: Three voltage controlled trapezoid generators with integral envelope shapers. A second output which lags behind t he first by one quarter of a complete trapezoid cycle. The amplitude and polarity of both outputs may be adjusted independently 50 that, if they are summed (on the patchboard), any continuous four-fine function which ends at the value at which it starts may be produced.

Envelope shaper is logarithmic to within 3 dB over its 60 dB range. Voltage control function of time parameters is ideally exponential to within ten per cent (of dependent parameter) over a range of 1,000:1. This permits a single voltage applied to all inputs to compress the time scale. Four voltage controlled filter/oscillators (Iow pass to resonating) mayalso be employed as a sine source. Four voltage controlled filter/oscillators (high pass to resonating): Si milar but complementary to low pass filters.

One octave filter bank. This consists of eight resonating filters, fixed-tune one octave apart, in the range 62.5 Hz to 8 kHz, separately controllabie.

Two voltage controlled reverberation units. Each spring unit has two elements with delays of 35 and 40 ms. Maximum reverberation time : 2.4 seconds.

Three voltage controlled slew limiters. Unity gain amplifier in which the output exactly follows the input at a rate whose maximum (slew) is defined by a control voltage. Range of slew control : 1 ms to 10 s.

Three transformerless ring modulators. Can be used in series for double or triple modulation.

Sequencer: One 256 event, six simultaneous parameter, digital sequencer stores 256 ‘notes’ and plays each at the correct time and for the correct duration. It simultaneously provides two voltages . one of which might be used to define pitch and the other loudness. It is capable of controlling three voices, each with duration, pitch and loudness. The 256 note storage may be distributed to each voice in any proportion. The second and third voices need not be used as such. The information to be stored and subsequently reproduced is presented to the machine as control voltages, which are most easily supplied from the keyboards. The machine may then be set to the edit mode. In this mode the sequence may be advanced at any speed, or step by step, so that each note may be modified or erased. A special feature allows time to be reversed. Ten controls are provided to adjust the amplitude of the sequencer’s output vo ltages. A further ten supervise the actual operation. Total storage capacity: 10,240 bits (of which 9,216 bits are normally used). Organisation of data : 36 bit words, each word representing one event. Start-of-event time (referred to start of sequence) : ten bits. End-ofevent time (referred to start of sequence): ten bits. Selection of one of three envelope shapers and one pair (out of three pairs) of digital analog converters. Also intern al functions: four bits. Data, for digital analog converters: two x six bits. Coding: The ten bit event time allows the start of each event to be defined to an accuracy of one part in two to the power ten. Thus if the dock is set to a rate of 100 pulses a second, each event may be adjusted forwards or backwards in increments of one hundredth of a second. The total sequence length would be ten seconds. The ‘end of event’ time, i.e. the time at which the key is released, is similarly recorded. Thus three control signals are reproduced, each being positive during the duration of a note intended for one of the three layers of the sequence. They are available at the patchboard as switching voltages which would normally go to the supervising inputs ofthe envelope shapers.

Digital Analog Converters: Of the six converters, three are of accuracy appropriate to exact control of pitch on the diatonic scale. Six bits give a range of 64 notes. If greater range and/or finer resolution is requ ired, th en the output of the second converter may be added to that of the first. In this case, the player might use one keyboard to defi ne a note on the diatonic scale, and the second to raise or lower that note by increments of one thirty-second of a tone.

Eight Multifunction Output amplifiers: Primarily intended to be the last link in the signal chain before the tape recorder or monitor. All eight are voltage controlled. Eight-way Fading/Panning Console Pin Matrix Patchboards: 60 x 60 (7,200) pin locations allow any input to be connected to any output by the insertion of a single cordless pin . The pins contain resistors 50 that several outputs may be mixed into a single input. All device outputs are fed to the board at a low impedance, blocking any reverse signal paths. Two patchboards are provided, one intended for control signals and one for aud io signais. A small number of interconnection patches between the patchboards are hard wired, as some signals can be used in both domains. It is also possible to route extern al signals to the patchboards by uSing the pins as jacks. All contacts, including the jacks, have a surface coating of silver.

Eight ac/dc input amplifiers These convert input signals to a suitable level and impedance to feed treatment devices. Two separate microphone amplifiers are supplied which can feed any two of the above channels. Four External Treatment Send and Returns: Provision for sending out to external echo plates and other equ ipment, and returning to the Studio. One frequency to voltage converter : This device accepts inputs from a variety of sources and produces a voltage proportional to the fundamental pitch of the note played. Circuitry is incorporated to remove overtones, provided their energy constitutes no more than 90 per cent of the total signal.

Two Envelope Followers : These produce a voltage proportio nal to the mean level of an audio signal. The output is passed through a second order low pass filter to remove ripple while keeping a fast response. Cutoff is about 50 Hz. Output amplitude is adjustable by a centre zero knob to give positive or negative excursions of up to 1 volt per 6 dB.

Two X-V joystick controllers: These give continuous control of two parameters togeth er. Two five-octave dynamically proportional keyboards: Five octave keyboards giving precise divisions of pitch or any other controlIabie parameter. In the case of pitch, the range would give anything between four and 40 notes per octave. By setting 12 notes per octave, the keyboard can be used as a normal melodic source. A second voltage output is proportional to touch, actually the velocity with which a key is struck. A third voltage switches positive when one or more keys are pressed. Note that the keyboard produces only one pitch voltage at any instant; when several notes are pressed, the voltage of the highest appears. Price: £7,500. Sequencer only: £1,500.


Version of Synthi, with following additional features:

32-note touch keyboard with no moving parts, contacts or springs. 256-event sequencer with dig ital memory. Independent control of speed and pitch. Additional features of the keyboard and sequencer include instant transposition, ran dom note generation, and independent ‘spread’ controls. Accompaniment trigger circuit. Instant patching facility with plug-in patches. New stabilised power supply. More fiexible, clearer to read, and easier to use patchboard. Price: £420.



Sound Sources : Three voltage controlled oscillators, each offering a selection of six different waveforms. Noise Source, generating white or pink noise. Microphone/Accessory Preamp for introducing extern al aud io signals for processing by the Mini Moog.

Sound modifiers : Voltage-controlled lowpass filter with contour generator and emphasis controls. Voltage-controlled amplifier with contour generator controls. Controllers: Keyboard (full-size 3t oclave) for controlling pitch and, secondaril y, filter.

Pitch Bender. Glide control for injecling porlamento between notes. Tune control for tuning entire Mini Moog. Three external control input jacks for extern al control of pitch, volume and filter. Trigger input socket for external trigger. A-440 reference tone hig hl y stabie oscillator for use in tuning the Mini Moog and other instruments to Standard Pitch.

Outputs : Main signal output (phone jack) with volume control. Headphone output (phone jack) with volume contro!. Auxiliary power output (two dc power sockets). Price: £660.


Instrument Complement: 901 voltage-controlled oscillator. 901A oscillator controller. Two 901B oscillators. 902 voltage-controlled amplifier. 903A random sig nal generator. 904A vollage-controlled lowpass filter. 907 fixed filter bank. 910 power supply. Two 911 envelope generators. 951 keyboard controller. Console panel No 11 including four input Mixer with ± and – outp uts jack muitip ies, reversibie attenuator, two control voltage and trigger outputs, two trunklines and power switch. Patchcord Complement: T en 30 cm cords. Eight60 cm cords. 30 cm switch trigger cord. 45 cm switch trigger cord. Switch trigger Y-cord. Price:  £1668.


Instrument Complement: 901 voltage-controlled oscillator. 901A oscillator controller. Two 9018 oscillators. Two 902 voltage-contra lied amplifiers.

903A random signal generator. 904A voltagecontrolled lowpass filter. 905 reverberation unit. 907 fixed filter bank. 910 power supply. 911 envelope generators. 950 keyboard controller. 956 ribbon controller. 991 filter-attenuator panel. 994 jack multiples panel. Blank panel with power-supply wiring and space lor one single-unit module. Two console panel No 3 each including four input mixer with ± and – outputs. Two trunklines. Control voltage switches. Attenuator. Console panel No 4 including control voltage switches. Attenuator. Trigger- and envelope-routeing switches. Three control voltage and trigger outputs. Console panel No 8 including power switch. Patchcord Complement: Eight 30 cm cords. Six 60 cm cords. Four 90 cm cords. Four 1.20 m cords. Two 1.5 m cords. Two 90 cm switch trigger cords. Price: £2,400.


Portable version ol IC.

Price: £2,400.


Instrument Complement: 901 voltage-controlled oscillator. Two 901 A oscillator controllers. Five 9018B oscillators. Two 902 voltage-controlled amplifiers. 903A random signal generator. 904A voltagecontrolled lowpass filter. 904B voltage-controlled highpass filter. 904C filter coupier. 905 reverberation unit. 907 fixed filter bank. 910 power supply. Two 911 envelope generators. 950 keyboard controller. 956 ribbon controller. 984 four channel mixer. Three console panel No 3 each including four-input mixer with + and – outputs. Two trunklines. Control/ voltage switches. Attenuator. Console panel No 2 including lowpass and highpass filters. Jack muitipies. Three control voltage and trigger outputs. One console panel No 6 including. Control voltage switches. Attenuator. Trigger- and enve loperouteing switches. Jack muitipies. Console panel No 8 including power switch. Patchcord Complement: Ten 30 cm cords. Six 60 cm cords. Four 90 cm cords. Four 1.2 m cords. Two 1.5 m cords. Two 30 cm switch-trigger cords. Two 90 cm switchtrigger cords. Price: £3,420.


Portable version of 2C

Price: £3,225.


Instrument Complement: 901 voltage-controlled oscillator. Three 901 A oscillator controllers. Nine 901 B oscillators. Three 902 voltage-controlled amplifiers. 903A random signal generator. 904A voltage-controlled lowpass filter. 904B voltagecontrolled highpass filter. 904C filter coupier. 905 reverberation unit. 910 power supply. Three 911 envelope generators. 911 A dual trigger delay. 912 envelope follower. 914 extended range fixed filter bank. 950 keyboard controller. 956 ribbon controller. 984 four channel mixer. 992 control voltages attenuator panel. 993 trigger and envelope voltages panel. Four console panel No 3 each including four-input mixer with + and – outputs. Two trunklines. Control voltage switches. Attenuator. Console panel No 2 Including lowpass and high pass filters. Jack muitipies. Three control voltage and trigger outputs. Console panel No 8 including power switch. Patchcord Complement: 1430 cm cords. Eight60 cm cords. Six 90 cm cords. Six 1.2 m cords. Four 1.5 m cords. Two 30 cm switch-trigger cords. Three 90 cm switch-trigger cords. Price: £4,455.

Sequencers A and B

The 960 sequential controller, 961 interface, and 962 sequential switch are modular instruments. Instrument Complement:

A         B

1          2          960 sequential controller

1          1          961 interface.

1          2          962 sequential switch

Blank panels with space and power-supply wiring for conversion to Complement B. 994 jack multiples panel (console models only). 910 power supply (mounted inside on console modeis, on top of case on portable models.

Patchcord Complement:

4          8          60 cm cords.

2          4          1.2 m cords.

2          3          30 cm switch trigger cords.

2          3          30 cm switch trigger cords.

1          2          special voltage trigger to switch triggercord.


(A): £1,158. (B): £1,980.


Portable version 013C. Price: £4,455.

AGENT: Feldon Audio Ltd, 126 Great Portland Street, London Wl N 5PH.


ARP 2500

Electronic music synthesiser comprising up to 15 voltage control modules between 20-way switchbanks. May be assem bied from any of the following basic ARP modules: 1016 dual noise/random voltage generator. 1047 multimode filter/resonator. 1005 modamp (balanced modulator and vc amplifier). 1027 sequencer (ten step, three layer). 1050 mixsequencer. 1036 sample and hold/random voltage unit. 1004 vc oscillator module. 1033 dual delayed exponential envelope generator. 1046 quad envelope generator. 1006 filter amplifier. 1045 voice module. Comprises oscillator, fi lter, amplifier and two exponential envelope generators. 1002 power supply Triadex Muse module. 1033 dual envelope generator. 1023 dual oscillator. 1035 triple modulator. Keyboard: five octave model 3001. Price: £5,400.

AGENT: F.W.O. Bauch Ltd, 49 Theobald Street, Boreham Wood, Hertfordshire.

ARP 2600/3604

Compact electronic music synthesiser including the following units: Three voltage controlled oscillators covering 30 Hz to 20 kHz in two ranges. Five waveforms including variable-width pulse, triangle, sine, square and sawtooth. One voltage controlled low-pass filter. Variabie resonance, dc coupled, doubling as low distortion sine oscillator. One voltage con tr lied amplifier with exponential and linear control response characteristics. One ac or dc cou pled ring modulator. Two envelope generators. One envelope follower. One random noise generator. Output continuously variabie from flat to -6 dB/octave. One bidirectional electronic switch. One sample and hold with intern al clock. One microphone preamplifier with variabie gain in 20, 40 and 60 dB ranges. One general purpose mixer with pan pot. Two voltage processors with inverters. One voltage processor with variabie lag. Doubles as low-pass filter. One reverberation unit. Twin uncorrelated stereo outputs. Two internal monitor amplifiers a.ld speakers with stereo 3 n headphones jack. One four-octave keyboard with variabie tuning , variabie portamento, variabie tone interval and precision memory circuit. Price: £1,360.

AGENT: F. W. O. Bauch Ltd, 49 Theobald Street, Boreham Wood, Herts.



Electronic music generator producing many perm utations (‘more than 14 trillion ‘) of melody lines Fixed output wavelorm suitable lor external treatment. Five octaves range. I nternal loud speaker Controls comprise volume, tempo, pitch, fine pitch four ‘ interval’ and four ‘theme’ selectors. Price: £250.

AGENT: AlJotTope ltd, 90 Wardour Street, London W1V 3lE.

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