Abstract: An audio system including audio processing circuit means interposed between a source of audio signals and a power amplifier. Power control circuitry including time delay means which respond to an on/off power switch for applying and removing power to the components of the audio system in a sequence which prevents audible pops associated with system start-up and shutdown.

Abstract: An automatic gain control circuit is disclosed which is direct coupled to phase opposed outputs of an IF amplifier and provides a DC control voltage for controlling the gain of the amplifier. The AGC circuit includes a peak-to-peak threshold detector and an integrating capacitor. The quiescent voltage across the capacitor is accurately established by a voltage divider network and a feedback network. Separate current sources are provided to establish dual time constants in the circuit so that distortion is minimized while accommodating a stop on station feature.