Recent Development in Hill and Dale Recorders

A new sound-on-disk recorder has been developed in which is used the principle of feeding part of the output of the system back to the input of the associated driving amplifier in properly controlled relationship. The use of this principle, which is widely used in feedback amplifiers, replaces the usual practice of providing dissipative elements for the control of an electrically driven vibrating system. Heretofore no practical application of feedback to electromechanical systems has been made, possibly because the requirements for stable operation of such systems are difficult of achievement. Through recent developments these requirements have been satisfactorily met. The new recorder is capable of recording on wax or direct-recording material without appreciable effect upon its characteristics, which include uniform response from 30 to 12,000 cps. and exceptional freedom from distortion. The recorder is extremely simple and affords easy means for field calibration from the feedback element, whose output is in direct proportion to the stylus velocity. These means also make available a monitoring voltage which, properly amplified, gives a precise aural picture of the stylus behavior during recording.

Print ISSN

0097-5834

Published

1938-01

Content type

Original Research

DOI

10.5594/J14718