Abstract: An apparatus for processing an audio stereo signal having left and right channels, for use with a video tape recorder having a monoral audio head comprises an analog switch assembly having an electronically controlled switch for each audio channel. A line connects the audio switch assembly to the monoral audio head and control equipment is connected to a video signal terminal of the VTR or video tape recorder. The control equipment utilizes a horizontal sync or synchronization pulse to produce a pair of complementary control pulses. The horizontal sync pulse is processed in a pulse multiplier to step up the frequency to at least twice and preferably about four times the highest audio signal frequency. By alternately controlling the electronically controllable switches to provide a sample of first one and then the other channel, a composite stereo signal can be recorded and then reproduced using the monoral audio head.