Improvements in and relating to thermionic amplifiers in noiseless sound on film recording systems

摘要

425,861. Converting. KOLB, O. K., 39, Beverley Court, Willesley Road, Chiswick, London, and FRENCH, J. L., 149, Horns Road, Ilford, Essex. June 23, 1934, No. 18615. [Class 38 (ii)] [See also Group XL] An arrangement for obtaining from an A.C. source 9, 10 steady D.C. for feeding sound film amplifiers comprises a rectifier 21 and smoothing circuit 22, 23 followed by a barretter 20 and gas-discharge tube 11 with internal tappings. Resistances 18 and 19 and electrodes 16, 17, ensure gas ignition throughout the tube. The valves of the direct current amplifier take their supply from terminals 12 (grid bias), 13 and 14 (HT). Supply voltage for the sound-current amplifier may be taken between terminals 12 and 15. Specifications 313,075, [Class 40 (v)], and 424,429, [Group XL], are referred to.