speaker protection

Thread Starter

apolo mahilane

Joined Apr 12, 2022
10
hi again to all
i want to design a speaker and amplifier protection circuit which can help in protecting my power amp , i mean the circuit which can help to protect my amp when the speaker output terminal touch each other accidentally,please if any on e have a good schematic diagram lease share with me.
thanks alot and with regards.
 

Ian0

Joined Aug 7, 2020
5,140
Unfortunately, this diagram doesn‘t have component numbers, but the protection circuit consists of 1N4148, BC182LB, 22nF, 100Ω and another 1N4148, and the same thing for the lower transistor; then the 10k 2x220uF, 2N4991 and BTA12-600B protect the speaker from amplifier failure.
 

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BobTPH

Joined Jun 5, 2013
4,906
But he asked for a circuit to protect the amp from a short at the speaker terminals.

Edited : Any good quality amp should have that built in.

Bob
 

KeithWalker

Joined Jul 10, 2017
2,354
What audio power levels are you planning on protection for? Is is a domestic entertainment system, a stadium sized PA system or an 800 Watt automobile subwoofer?
The safest protection by far is some good polarized output connectors that can not be accidentally shorted, with female connectors on the amp side and male on the speakers.
The second best protection is intelligent use of the volume control and power switch. In other words, don't play with the speaker wires when the power is on and the volume is turned up!
The third is to make sure that the speakers are capable of handling the maximum output from the amplifiers.
Anything beyond that is overkill.
 
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MrChips

Joined Oct 2, 2009
26,099
It is known practice to insert incandescent light bulbs in series with the loudspeaker to protect the loudspeaker.
I experienced this once when a loudspeaker was overloaded and I saw a flash of light inside the speaker cabinet. Thank goodness it was the bulb protection kicking in.

You could install the bulb inside the amplifier.
 

Ian0

Joined Aug 7, 2020
5,140
A lamp in the output is going to result in compression of the signal. I’m not sure if a polyswitch would introduce distortion.
One thing I do know about polyswitches, is that in an over voltage situation they catch fire, so make sure it is rated for the sum of the positive and negative supplies.
Distortion could be avoided by putting the protection device in the supply rail after the smoothing capacitor.
 

Thread Starter

apolo mahilane

Joined Apr 12, 2022
10
thanks alot for sharing ideas but my concern is not about a speicon iam looking for a protection circuit, i have seen some huge watts amplifier having that kind of protection thats why i am asking for some one who have idea on that
 

Thread Starter

apolo mahilane

Joined Apr 12, 2022
10
What audio power levels are you planning on protection for? Is is a domestic entertainment system, a stadium sized PA system or an 800 Watt automobile subwoofer?
The safest protection by far is some good polarized output connectors that can not be accidentally shorted, with female connectors on the amp side and male on the speakers.
The second best protection is intelligent use of the volume control and power switch. In other words, don't play with the speaker wires when the power is on and the volume is turned up!
The third is to make sure that the speakers are capable of handling the maximum output from the amplifiers.
Anything beyond that is overkill.
It does; and it also protects the speaker from DC conditions at the amplifier output.
exactly what am looking
 

Thread Starter

apolo mahilane

Joined Apr 12, 2022
10
Unfortunately, this diagram doesn‘t have component numbers, but the protection circuit consists of 1N4148, BC182LB, 22nF, 100Ω and another 1N4148, and the same thing for the lower transistor; then the 10k 2x220uF, 2N4991 and BTA12-600B protect the speaker from amplifier failure.
so Ian the circuit you uploaded can solve my concern?
 

Ian0

Joined Aug 7, 2020
5,140
Yes, with the correct selection of resistors. The original was an amplifier that was rated 110W into 4Ω, so the peak current would be 7.5A.
Bear in mind that it is much easier to protect an amplifier from a dead short than from a load that is just slightly too low impedance.
 
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