This is a simple active speaker protector circuit which has a very important use, expecially to protect the loudspeakers of a audio system. It prevent the speaker from noise sound when we turn on the power amplifier. The circuit drives the speakers after 3 to 10 seconds so that the source of the same stabilizes and stops generating cracks and noises that could damage both the speakers and the output transistors of the amplifier. This circuit powered using a 12V regulated power supply. If you have a high power audio system, you may try to build this circuit and mount the circuit in the amplifier box.
Bottom PCB Layout Design | Active Speaker Protector
Top PCB Design | Active Speaker Protector
Speaker Protector Circuit Connection
Active Speaker Protector Part List
- 5-pin 12-volt Relay – 2
- Transistors 2SC945 – 2
- Transistor 2SC9013 – 1
- Diodes 1N4007 – 5
- Elco 220 uF / 50V – 2
- Resistor 10 KOhms – 4
- Resistor 1 KOhms – 1
- Resistor 39 KOhms – 1
- Large 3-pin connectors – 2
- Small 3-pin connector – 1
- Trimpot of 220 KOhms or 500 KOhms – 1
Could I use 1n4148 diods substitute to the 1n4007?
Trimpot adjusts power on delay time
I’d like to build this protector. May I ask what is the role of trimpot and how can I adjust it numerically. Thanks.