An Integrated Quadraphonic DC Volume Control

Because of the space requirements, poor tracking capabilities, and connection difficulties of four-ganged potentiometers for use in quadraphonic volume controls, many manufacturers of four channel equipment have been reluctant to use a single master volume control. Instead they have tended to use pairs of dual controls, typically connected as front and back gain controls combined with a pair of left/right balance controls. This results in even poorer tracking and in virtually unrepeatable balance setting for any room arrangement other than an ideally symmetric one where the listener is located on the axis requiring equal level settings on both gain controls. This paper discusses a four channel monolithic volume control whose gain is set by a single dc control voltage, with the ease of connection and space savings this implies. In addition to good channel to channel tracking, it has a fully flexible set of dc controlled balance functions and the capability of gain variation with logic enhanced 4-2-4 matrix recording systems. 1