GB1295994A - - Google Patents

Abstract

1295994 Electrophonic musical instruments CHICAGO MUSICAL INSTRUMENT CO 19 April 1971 [25 May 1970] 22110/71 Heading G5J In. an electronic keyboard instrument, e.g. organ, having two sections of "keys" operating individual tone generators, the notes of a chord held in the first section are reproduced automatically in arpeggio form in the second section on operating an arpeggio switch, irrespective of the notes being manually played in the second section. A typical tone generating circuit 10 of the second section is normally operated by a key and switch 16, 17, but may be activated by a signal passing through the gates, e.g. 29 of the arpeggio section via leads, e.g. 38, at any time. A similar layout of tone circuit C less the connection 38) is provided for keys of the first section and in addition a further switch arrangement 31, 30, Fig. 4, associated with each key connects a standing 20 V potential via lines 32 to the gates 29. When a suitable negative potential is applied to the base of the gate from the arpeggio switch circuit, Fig. 1, the gate becomes conductive and the corresponding second section tone generator is energized. The key switches interconnect notes spaced an octave apart, the switch signal of an operated key being presented to all gates representing octave separation of that particular note through diodes 33. The signal to open the gates is presented to each gate (or set of 3 adjacent gates) in turn via the lines 28 by capacitor discharge from a cascade circuit 24 when a ramp voltage is applied from the output of device 23 on operating the arpeggio switch 19 (Fig. 1). The switch may be foot operated. A reset position is incorporated in order that the arpeggio may be terminated within the normal cycle. The length of the "ramp" is adjustable to vary the rate at which the arpeggio is performed. A further connection via resistor 39 may be provided to allow a particular pulse from the cascade circuit to operate on two groups of gates in order that a chord having well spread notes shall not be reproduced by the arpeggio section with uneven timing.