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2009/83/1 Voltage controlled oscillator (VCO) with ring modulator, custom built, metal / plastic / electronic components, probably made by Tristram Cary, England, 1962-1966. Click to enlarge.

Voltage controlled oscillator (VCO)

This object is an example of a piece of electronic equipment built (probably in the early 1960s) specifically for audio synthesis. It is custom built, possibly by Tristram Cary and was used in his early studios established in London in the mid-1960s. It has a unique organisation of components, some off the shelf, some hand built, and was clearly modified as required during its useful lifetime. It may have been used in the construction of sounds for the Daleks in early episodes of the BBC's …


Object No.


Object Statement

Voltage controlled oscillator (VCO) with ring modulator, custom built, metal / plastic / electronic components, probably made by Tristram Cary, England, 1962-1966

Physical Description

This is probably a hand-built and very early version of a device known as a ring modulator. It consists of a voltage controlled oscillator (the device which is at the heart of all analogue audio synthesis equipment) with a number of presettable voltage setting potentiometers selected with a large rotary switch.

It is mounted in a black metal plate (approx 40 x 45cm) with numerous controls built into it. Across the top it has two rows of 12 presettable potentiometers which are wired to a 30 position rotary switch. The switch is set up to select from any one of the presets, two very finely resolvable potentiometers having vernier controls or a further four external voltage inputs. In the centre of the panel is a rectangular plastic panel with a white surface in which the two vernier controls are mounted. On the regions of the surface around each there are traces of control position markers written in chinagraph pencil. There is a voltage level meter to the right hand of this central panel. Below there are, from left to right, a single control knob, a two position rotatable switch, three output jacks, three columns of three control knobs for setting amplitudes of a square wave and (what appear to be) two triangle or sawtooth wave oscillators. The outputs of the three oscillators are summed together to produce an output signal. These controls have arrows in strips of white tape running between them indicating the connections of the circuits and the signal flow between them. Many of the controls are marked with coloured paper dots to enable the user to distinguish which controls appear at which outputs or contribute to those output signals. There are also labels in dymotape at some of the controls which indicate their purpose.

On the reverse are the working elements of the various control components, plus several circuit boards, the functions of which are controlled by these components. The circuit boards consist of two printed wiring assemblies, which are probably off-the-shelf oscillators, and two prototype circuits built on strip board (Vero board). Each has an array of electronic components consisting of transistors and passive devices soldered onto it. There is an array of wires which connect up the various devices.


Various labels in dymo tape.



407 mm


483 mm


176 mm




Tristram Cary (b. Oxford, England, 1925 - d. Adelaide, 2008) was a pioneering English composer who worked in electronic music. His first studio was set up in England about 1965. He was instrumental in the development of the audio synthesiser being, at least in art, the impetus behind the development of the Electronic Music Studios' (EMS) Synthi A, and VCS3. In 1974 he moved to Australia, first to Melbourne University to teach electronic music using the EMS Synthi 100 at Melbourne University and subsequently to Adelaide to teach composition and electronic music at the Elder Conservatorium, University of Adelaide.

He gained his knowledge of electronics as a Naval radar operator during WWII. During this period he heard of the development of tape recording and he realised that he could edit and make musical works by cutting up the tape with a razor blade and re-splicing it. As he later said:

"It occurred to me that … here was a chance to have a new sort of music altogether. The editing capacity meant that you could cut sounds together that were not normally together." [David Ellis, "Music pioneer celebrates milestone", Lumen, The University of Adelaide Magazine, winter, 2005, ]

After the war he returned to university at Oxford and then went on to Trinity College of Music in London. He began to experiment with electronic sound in 1949, bought his first tape recorder in 1952 and began composing electronic and orchestral music. His first great success was the score for the film The Ladykillers (1955) starring Alec Guinness and Peter Sellers. He continued to write film and television music and is famous for producing the music for several episodes featuring the Daleks in the BBC's Dr. Who.

Around 1965 Bob Moog began selling his early synthesisers in America. In 1967, Cary established an electronic music studio for the Royal College of Music and assembled his own studio in his London house. Up until this time most electronic music had been produced within large workshop style studios using an assemblage of electronic workshop test equipment (function generators and filters and the like) and hand built special purpose devices.

Cary met and consulted for Peter Zinovieff who had established a private electronic music studio in Putney (on the south bank of the Thames in London). Zinovieff had purchased a DEC PDP-8 minicomputer to explore computer music and established it in the studio. David Cockerell was an experienced electronic designer who built a ring modulator that gave the distinctive sound to the Dalek's voices in Dr. Who. He became Zinovieff's engineer in 1968. Cary, Zinovieff and Cockerell, through their common interest in electronic sound, worked together to come up with an audio synthesiser that would be more portable and a lot cheaper than existing devices such as the Moog synthesisers.

Legend has it that the Australian composer Don Banks who, in the 1960s was resident in London, also wrote film music and was interested in incorporating jazz into his compositional repertoire, had asked Zinovieff and Cary to make him a small voltage controlled synthesiser. With Cockerell as the main electronic designer, they mapped out how to build what became the VCS1, of which two were built. One of those two is in the collection of the Powerhouse Museum [H9953-13]. By 1969 they had established the company Electronic Music Studios and began marketing the VCS3 (a larger version of the VCS1) with 3 VCOs, a VCFilter, an envelope generator and other interesting modules. Again the electronics were designed by David Cockerell, the case was designed by Cary and the whole project was supported by Zinovieff. Apart from its small size the most interesting aspect of the VCS3 as against the American synthesisers of the period was that it used a small plug settable patching matrix to connect outputs of sources to inputs for control of audio signals.


Credit Line

Gift of John Cary, 2009

Acquisition Date

16 October 2009

Cite this Object


Voltage controlled oscillator (VCO) 2021, Museum of Applied Arts & Sciences, accessed 3 December 2021, <>


{{cite web |url= |title=Voltage controlled oscillator (VCO) |author=Museum of Applied Arts & Sciences |access-date=3 December 2021 |publisher=Museum of Applied Arts & Sciences, Australia}}