Amp Protection Circuit - Here!

[Samuel Jayaraj]

If you have noticed, I posted this thread initially 4 years ago. Strangely, none showed any interest then. It is quite some time and it will take me a while to locate the original articles from Elektor. Some one else could pitch in here; these appeared sometime in 1986 (in India).

[richie00boy]

LOL sorry, it's EDL's fault I did not notice the date of your posts. Don't worry about it.

[boraomega]

As a humble contribution to this thread, here is the link to a few posts in another thread where I published my OMNI-protection system:
http://www.diyaudio.com/forums/showt...777#post649777

Schematic, PCB, layout and short explanation are given in several consecutive posts. Someone might find it useful?! That works nicely and reliably.

[Bensen]

Hi Samuel,

I use this DC-protection + Delayed speaker connection in all my amps with good results. It reacts pretty fast on a DC-signal.

Concerning the temperature protection, I had some problems with an "oscillating' relay, as of the hysteresis was very litttle. I managed to get a good working on, with a "big" (+-100µF)condensator over the relay-coil if I remember correctly.

greetz
Ben

[matic]

Can i make only one DC protection an use two R7, (which is 100k) one conected to Left and other to Right channel? If one chanel blows up so it pass the DC voltage will it damage the other chennel? Dc will pass through 2x100k. If this can be done, can i do this allso with 10k or 33k input R on protection circuit?

[JKoch]

Hi Samuel

Your Amp Protection Circuit is very interesting for me: it comletly protect amplifier and speakers. But I have some questions:
- if 12V AC should wired to AC2 ?
- if Thermal Sensor should be conect to IC1 ?

Many thabks for your reply.

JKoch

[unclejed613]

i've got a fairly simple one..... comes from the Apt-1
it's fairly simple, includes turn-on delay, dc protection and SOA (safe operating area) protection for both channels.

if the file sizes are right, these should upload easily.....

[unclejed613]

this is the other half of the relay circuit

[unclejed613]

and here's the soa detectors, and where they connect to the output transistors (build for each channel) the output of these detectors connect to the relay driver circuit. all that.s needed for this is a handful of transistors and a dual op amp and a relay.....

some recalculation of rc values in the soa detectors may be required for other output devices. the output devices in the apt-1 were MJ15022/23.