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Subscriber: null; date: 24 January 2020

Electronelocked

  • Hugh Davies

Electronic organ, several models of which were designed by Leslie (E.A.) Bourn from the early 1930s and manufactured by the John Compton Organ Co. (later Compton Organs Ltd) between the mid-1930s and 1970. In 1926 Bourn approached John Haywood Compton with a proposal for the production of a ‘pipeless’ organ, and was invited to join the staff of Compton’s company. By about 1928 Bourn had abandoned his original electromagnetic tone-wheel system of sound generation and had developed his pioneering electrostatic system. It is based on 12 identical electrostatic tone-wheels, which are rotated at different speeds, by means of a synchronous motor and a set of pulleys, to produce all the semitone intervals in an octave. Each tone-wheel mechanism consists of two discs. A Bakelite stator disc, 12.7 cm (5”) in diameter, has engraved on it a set of concentric sinusoidal waveforms, corresponding to a fundamental pitch and its octaves; these grooves are filled with a metallic conductive material. A rotor disc, containing appropriately positioned electrodes, is rotated at about 1 mm distance from the stator. When an electrical potential is applied to one or more of the waveform rings, a corresponding voltage is induced in the electrodes, the mechanism forming the equivalent of the two plates of a capacitor. Gliding sounds can be produced by a relay that briefly slows down the motor, it can be activated only when all the keys are released.

A simple version of Bourn’s system, known as the Melotone, patented by Bourn in 1932, was first used for solo purposes in some Compton cinema and theatre organs in the mid-1930s; experience in its use led to the development by 1938 of the Theatrone, a fully electronic theatre organ. Although hybrid organs with solo Electrone sections were first demonstrated in 1935, it was not until 1938 that a complete Electrone organ was produced (its name was chosen by Compton to avoid potential problems over the use of the word ‘organ’ for an electronic instrument). Manufacture soon began, but it was interrupted by the outbreak of war (some 80 instruments were built up to early 1940), and not until after 1945 did production get under way on a large scale; in all about 20 models were made. In the smaller models each of the 12 tone-wheels carries only seven sinusoidal waveforms, covering a pitch range of six octaves; timbre is created (as in the early Hammond organ) by ‘borrowing’ other (equal-tempered) pitches (in some cases additional tone-wheels running at different speeds are incorporated to provide ‘natural’ partials, in particular the seventh). In the larger models up to five different waveforms are provided for each note (each disc carrying up to 30 rings), so that various timbres can be produced without the need to use overtones based on tempered pitches. Some models were intended for churches and were made in alternative versions that offered Baroque or Romantic registrations; others were designed for concerts and for home use (including one confusingly called the Melotone introduced in 1952, but distinct from the original). Most Electrones have two manuals and pedals, though a number of three- and four-manual custom-built instruments were produced from about 1950, one of which was temporarily installed in London’s Royal Festival Hall in 1951. Some of the organs incorporate an electric chime unit and (from 1965) a slowly rotating ‘chorus’ loudspeaker.

Bourn continued to develop the Electrone and its electrostatic system until his retirement in the late 1960s. Compton died in 1957 and in 1964 the pipe organ division of his company was sold to Rushworth & Dreaper. Production of Electrones continued at Comptons until the end of the 1960s. In 1970 the electronic organ section was taken over by Compton-Makin, which became J. & J. Makin Organs Ltd in 1973; an updated version of the Electrone was then briefly manufactured as the Makin organ. Makin replaced Bourn’s outdated electrostatic design with an analogue design in the late 1970s and then with digital methods by the early 1990s. The construction of some of the smaller models was also continued, between 1970 and 1974, under the name Compton-Edwards in Mirfield, Yorkshire.

Bibliography

  • ‘Electrical Organ Tones: Technical Details of the Compton “Electrone”’, Wireless World, vol.36 (1935), 514ff
  • L.E.A. Bourn: ‘Electronic Organs’, The Electronics Forum, no.13 (1949), 13ff
  • R.H. Dorf: Electronic Musical Instruments (New York, 2/1958), 177
  • C.A. Taylor: The Physics of Musical Sounds (London, 1965), 179
  • D.T. Williams: ‘The Compton Electronic Organ in the Chapel of Bromsgrove School. Worcs.’, MO, vol.90 (1966–7), 254ff
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