Abstract: A protective circuit for a loudspeaker connected to the output of an audio amplifier, in which a predetermined fraction of the voltage derived from the output of the power amplifier is peak rectified and stored in an accumulator provided with resistors for leaking charge from the accumulator at a predetermined rate. The voltage across the storage capacitor is normally maintained blocked in respect to application to a diode control circuit for by-passing input signal to the power amplifier. When the voltage across the storage capacitor attains a sufficiently high value, control signal is applied to oppositely poled diodes, to vary their back biases, and the diodes provide a controlled shunt path to ground for peaks of the signal applied to the input to the power amplifier.