Power Amplifier Speaker Protection Circuit Schematic

While switching a power amplifier on, a loud thump sound is heard to sudden heavy discharge current through the speaker at the time of power on. This current may damage the speaker, especially in case of direct coupled amplifier.

PARTS LIST
R1	5KΩ Preset
C1	1000μF 25V
C2	0.1μF (104)
D1	IN4001
Q1	BC107
RL1	9V 500Ω Relay
LS1	Speaker

The circuit given here protects speakers from the current surge. When the amplifier is off, relay switch is also off. When the amplifier is switch on, R1 and Ci provide delay of a few seconds to switch the transistor on which energizes the relay.