protection for tweeters

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This is my protection for tweeters,tested and work well,adjusts the trimmer potentiometer before the amplifier to clip, LED lights,and relays are switched tweeter gets reduced signal through the resistor 100 oma.If someone wants to improve results can simulate anything to add any comment is welcome.
signal taken from the output of the tweeter crossover.
 

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If the rectified voltage is too high e g. 25vdc you could overload the relay coil. Also, the capacitor, I think its microfarad not millifarad right? still, it can cut into the signal peaks. what do you expect from this circuit over the standard light bulb?
 
I prefer light bulb, or PTC parallel to R=22 ohm / 20W (or 40 W). Simple, tried and tested.
Your solution has an abrubt action and that is not good, also R=100 ohm is too big, use 22 ohm/20W (or 40W - depends on driver) instead. ViennaTom also has a valid point regarding the overloading.
Look at Dynacord datasheets - they have more elaborate protections with reley and light bulbs.
 
Regular 1N4007es may be a bit slow (a similar circuit I designed and use, uses the UF series Diodes).
the Polarity of your LED is reversed (simple typo I am sure).
and there is nothing to limit the current through the Relay and LED so in extreme cases they may fail.
also disconnecting tweeters from a 2nd order cross over can be problematic, with some less stable amplifiers, as it will essentially leave a tuned circuit across the amplifier which CAN (but hopefully won't) result in stability issues....
your basic thinking is reasonable however,
This is my design (similar thinking but somewhat more developed):
Australian Technical Production Services
 
I can agree on the stability issue from personal experience. When you wire the relay contacts differently this problem is ameliorated though. You simply connect the resistor accross the opening contact instead of having it in series with the closing one and you will never have a no-load situation for your crossover.

I once did something similar and I used the transistor as current source which guarantees that the relkay coil can't be overloaded. You wiull have to take care of the Vce and dissipation of the transistor however.

I can maybe undig my old circuit diagram.

Regards

Charles
 
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