GB1365716A - Musical devices - Google Patents

Abstract

1365716 Electrophonic musical instruments SEEBURG CORP OF DELAWARE 15 Nov 1971 [13 Nov 1970] 52966/71 Heading G5J A tonal rythmic accompaniment is provided by a tone generator system which is automatically actuated to produce one of a number of selectable patterns of notes of a scale and controlled by an instrumentalist to select the tonality of the scale. In a first embodiment, the tone generator system comprises nine unijunction oscillators 119-127, Fig. 3, each producing a tone signal having a predetermined relationship to a tonic. The tone signals are connected via a frequency stabilizing flip-flops 145, voicing network 165-169 and sustain keying circuit to a transducer. The keying circuits are actuated in any one of five selectable sequences by pulses applied at 109-117 to sustain capacitors 160 from a logic circuit fed by a pulse generator, Fig. 1 (not shown). To contro the tonality of the notes produced, the instrumentalist closes one of the pedal switches 171- 183, Fig. 4, to apply positive voltage to the base of a corresponding transistor 218 and so short a selected point of the resistor chain 184-197 to ground. This selects the voltage on the base of transistor 223 which controls the voltage applied to the anodes 132 of the unijunction oscillators, Fig. 3. In a second embodiment, Figs. 6-8 (not shown) a single unijunction oscillator is used and the sequence of notes is produced by superimposing on the anode voltage selected by the instrumentalist an automatically selectable voltage in the form of the voltage drop across a number of resistors selected by nine field effect transistors.