GB378069A - Radio-electric musical instrument with key board and thermionic valves - Google Patents

Abstract

378,069. Electrical musical instruments. COUPLEUX, E. E., 24, Rue Esquermoise, Lille, Nord, and GIVELET, J. A. M. V. de P., 24, Rue Bois-le-Vent, Paris, both in France. May 1, 1931, No. 12924. Convention date, Nov. 15, 1930. Addition to 359,967. [Class 88 (ii).] A keyboard musical instrument as in the parent Specification has a thermionic valve for each note, the circuits from valves of notes of the same name in the different octaves being connected together in parallel, Figs. 1 and 2 (not shown). The output circuits of the groups of notes of the same names either are each connected to its own amplifier and loudspeaker Fig. 3 (not shown), or are each connected to a primary of a multiprimary transformer of which the single secondary is connected to an amplifier and common loud-speaker, Fig. 4 (not shown). Fig. 5 shows a transposing device consisting of a pedal-actuated bar G carrying soft-iron blades I nearer to the cores n of self-induction coils s in the note-circuits. One of two manuals may thus be sharpened to any desired degree to give celeste notes with beats. In Fig. 6 the note circuit for key T1 is closed at contact d1 and connected through the transformer Tr to the moving coil e of a loud-speaker. Sounding of the note however is delayed till a second contact d2 is made, energizing the exciting winding E of the loud speaker. The retardation and the amplitude of the note are carried by an adjustable inductance Si. As open to inspection under Sect. 91 (3) (a) the Specification states that a note may also be introduced softly, avoiding percussion in the loud-speaker, by arranging the key contacts, in the filament heating circuit of the valve with a shunt resistance or capacity to avoid sparking, and that changes of timbre may be obtained by varying the ferro-magnetic saturation of a transformer or a loud-speaker core. This subject-matter does not appear in the Specification as accepted.