GB900212A - Electrical musical instrument - Google Patents

Abstract

900,212. Electrophonic musical instruments. LOWREY ORGAN CO. Aug. 15, 1958, No. 26330/58. Class 88 (2). In a two-manual instrument having a coupler and using thermionic-valve tone generators, each key has a movable contactor which engages an associated fixed contact when the key is depressed, positive potential for activating the tone generators being connected to the fixed contacts; the circuit is such that the fixed contact of a key of the lower manual is connected to its associated tone generator only when the lower manual key is depressed and the corresponding upper manual key is raised. As shown in Fig. 1A, closure of switch 21 couples the upper manual to the lower, the circuit ineluding the movable contactor 11 of the upper manual key so that there is no possibility of " robbing," i.e. unwanted connection between the upper bus-bar 23 and the lower bus-bar 17, through the simultaneous depression of corresponding keys in both manuals. In a modification, Fig. 2, this " robbing " is prevented and coupling effected by a gas-tube NE2 which fires with a potential difference of 120 volts but not 60 volts. In a further modification, Fig. 3 (not shown), the gas-tube NE2 is used in conjunction with a condenser and a manual or pedal control to sustain notes after the release of the corresponding keys.