dc output protection

So i'm slowly acquiring parts for an amp...
I'm also lazy to a point. I have a 1050 va transistor in the power supply. So naturally i want a premade cheap output protection circuit for dc. Preferably small in size doesn't need to be perfect as long as the speakers and amp don't blow up if has to be used.
What do you guys recommend?
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
And therein lies the rub :D

Cheap, small and guaranteed to protect amp and speakers don't figure in the same sentence. A 1050VA transformer has some serious current delivery capability.

Most cheap offerings fail in the relay specs. It has to be able to break the full current (that is flowing in an inductive circuit... the woofer) without the resulting arc welding the contacts closed.

Maybe someone has an off the shelf recommend. A more involved DIY prospect involves using FET's as series switches (to make a solid state relay)
 

andrewlebon

Member
2008-02-13 2:25 pm
dc protection

Try it
warm regards
andrew lebon
 

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Hi,
Just to let you I am working in a controller that will protect the speakers output from high constant current or shorted. The only problem it is that it used a micro chip. These are the options that will perform to protect the speakers.
1- Slowly ramp the AC voltage on power ON/OFF using a triac at zero crossing. This will prevent the inrush current of the transformer.
2-Mute /delay the speakers output in the power ON/OFF.
3-Protect the outputs transistor/Speakers on Heat sink high temperature.
4-Monitor the speaker outputs for a constant high current. If the current reached the trip setting it will automatically set the amplifier in protect mode.
5- Working on to preventing the amplifier to power ON/OFF constantly when losing the commercial power intermittently.

I have it installed in a LM3886 amplifier and it is been working flawless for 6 months.
I am planning to make a video showing all the options.
Attached are two pictures showing the controller.
 

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