This limiter circuit use to avoid clips on a mid-power amp.

It controll and decrease the input of amplifier by sensing the amplifier output 

The circuit is a single layer pcb with very very simple design.

It uses a little components 2N5551 & 2N5401 transistors, diode 1N4148, electrolite capacitor and some resistor.

It need connect to your main power supply amplifier by using two resistor 2k2.

but this resistor value need to change to match with your power supply voltage, just calculate it current for the 2nxx transistors.

The trimpot use for adjust or finding a resistance value dan match with your amplifier, then you can change to through hole resistor after found the resistance value.