DC-protection?

[Skorpio]

I was wondering about how many of you out there are using loudspeaker protection on your DIY amps?

And if you do, what circuit do you prefer?

Do you have some examples from real life where a amp has destroyed the speaker?

As I understand it it is the DC-coupled woofer that is the critical part. It can handle DC for a while but long enough for the main fuse to blow and the caps to be decharged?

[Nordic]

Sadly I've witnessed it twice....

My current project is a protection board, based on the cheap upc1237 chip.

Just got the parts yesterday... Working from datasheet schematic, which seems fine...

checks AC voltage before rectifier for power on/off , checks DC voltage after rectifier, checks output for DC offset, can be adjusted for Rails from 25 to 60V by just changeing resistors...

Cost of components $6-$7 if you are willing to go with less expensive components....

I found some nice sealed 16A relays for about $2 each... (by far the most expensive part of the circuit...)

[felixx]

UPC1237 is the easy way.I use that in more than 10 solid state amps and work fine.

[alex mm]

Is not tested , but possibly PCB for uPC 1237 HA

[zener_diode]

I destroyed 2 very nice woofers before with DC... just wasn't paying
attention and forgot to solder the input transistors... leading to DC
offset on the output.