Abstract: A TV SAP/stereo audio system includes a DC switch for selectively coupling the output of a stereo decoder and the output of a SAP detector to a stereo amplifier. A DC voltage, representative of the SAP carrier level, is developed and applied to a pair of threshold transistors. The lower threshold transistor is driven conductive when the DC voltage is below a first voltage and the upper threshold transistor is driven conductive when the DC voltage is above a second voltage. The threshold voltages are established by a pair of voltage dividers. A SAP control transistor is coupled to the collectors of the threshold transistors and is driven conductive when either threshold transistor is in conduction. The SAP control transistor is connected to the DC switch and prevents coupling of the SAP detector output to the stereo amplifier when it is conducting.