An audio system having a main chassis including an audio preamplifier and a remote chassis including a power amplifier has a clipping level detector circuit in the remote chassis for detecting the onset of clipping by the power amplifier and has a gain control element in the main chassis for controlling the gain of the preamplifier. An extra control line in the wiring harness connecting the main chassis and the remote chassis is avoided by multiplexing the clipping signal and the mute control signal on a single control wire.