GB428399A - Improvements in or relating to electrical control systems for illumination apparatusassociated with musical instruments and producing spectacular effects - Google Patents

Abstract

428,399. Theatrical appliances. COMPTON ORGAN CO., Ltd., J., Chase Road, North Acton, London, and MIDGLEY, A. H., 9, Priory Hill Avenue, Sudbury, Middlesex. Jan. 1, 1934, No. 96. [Class 132 (i)] [See also Group XXXVIII] In an organ or like musical instrument, associated with a lamp or lamps 17, for producing spectacular luminous effects, the intensity of illumination is automatically varied in accordance with the number of playing keys depressed simultaneously. Alternatively or additionally, the colour of the light produced by such an illumination apparatus may be so controlled. Control is through a relay 3, energized by the variable voltage drop across a resistance 2, included in the circuit controlling the sound produced by the organ. The stopkeys and swell-pedal may also assist in the control. In Fig. 1, the number of note-keys C1, C2, &c. struck simultaneously, controls the voltage-drop across the resistance 2 by introducing the corresponding note-magnets D1, D2, &c. into the circuit. This voltage-drop passes through amplifier and detector valves 4, 5 to the grid of a valve 15, the anode circuit of which includes the lamps 17, which are all of one colour and of an initial intensity which can be varied by means of a tapping 12<1> in the amplifier. The valves all have indirectlyheated cathodes and the valve 15 is gas filled. To provide for colour-variation, two such amplifiers may control lamps of different colours and act oppositely so that one colour brightens whilst the other fades. In Fig. 2, the stop-keys 20d1, r1 s1, &c. also operate the corresponding switches 24d, r, s of amplifiers 3d, r, s controlling differently coloured lamps 17d, r, s, the note-keys C1, C2, C3, &c. as in Fig. 1, being connected in the circuit of resistances 2d, r, s, introduced by switches 25d, r, s controlled by the stop-keys, and also varied automatically by the swell-pedal 26. A similar control resistance may be inserted in the circuit of the drums, cymbals, and like effects.