speaker protection (OR) overload protection

[myanmar]

Hello Friends,

I want to protect my speakers & amplifier.

I saw in yamaha amplifier that include spk protection or over load protection.

That is only slide volume control.
that label
4ohm 10W,20W,50W,.....
8ohm 10W,20W,50W,.....
That has alarm LED flash when I increase volume to reach that power output.

I want to put that in my amp.
( Bridge With IRF 540 & IRF 9540 )


I have one design.
but that is not with variable resistor.
That is with pairs of resistors to change to get desire watts.

Pls, help me with VR.

Sorry for my poor english.

Thanks.

[myanmar]

Here is my overload protection.

Pls, Help me.

[AndrewT]

Hi,
you have posted a LED indicator that monitors voltage.

It stays off until the Vbe of Q1 is triggered and the thyristor then switches on the LED giving a flash until the thyristor un-latches.

This is neither speaker protection nor amplifier protection.

ps. where's your amp schematic?

[myanmar]

Hello AndrewT,



You can find my amplifier schematic in that link.
http://www.diyaudio.com/forums/show...&threadid=80972

Thanks for explain.

I already tested that circuit.
And then I put ( Variable Resistor + Resistor ) instead of Variable Resister.

Now my calculation is
R1 = 470
R3 = 45 K
RV1 = 2k Variable Resistor + 1K resistor.

According from the table.

That LED can indicate about (300W to 50W for 4ohm Load )
OR ( 150W to 25W for 8ohm Load) when I turn variable Resistor down to up.


My assumption is true or false ?

Sorry for my poor english.

[myanmar]

Hello Friends,

Can I add another bridge diode ( 4 diodes ) in my LED indicator for stereo input ?

Any change in LED indicator for measure watts ?

Watts per channel increase or decrease or same ?

Pls, Help me.

[richie00boy]

To add another channel you just build another unit the same.

As Andrew has said this is a useless piece of equipment and will not protect anything. It's just a gimmick flashing light. Your ears will tell you that something is wrong long before this indicator will.

If you want a VU meter you would be better with a proper one using one of the LM3819(?) chips.

If you want to protect your speakers use a Velleman K4700 or K4701 kit or ESP Project 33. And learn to listen to the sound of your system.

[myanmar]

Hello richie00boy,

You always help me.
Thanks you very much.

I will learn & test that.

[richie00boy]

Thanks and good luck with your project.