Protection circuit

[palesha]

I am building one discreet 100w home subwoofer. Audio activated on & off ( after the audio signal missing for 15 minutes) plus dc offset protection circuit is required. I have seen one circuit with single relay in one subwoofer circuit. I will like to see if our diy friends have built the similar circuit. otherwise suggestions in the matter will be appreciated.
Mahendra Palesha

 

[tiroth]

Rod Elliots' Project 33

(You'll need to supply the timer circuit externally.)

 

[fcel]

How about this?
http://www.audioxpress.com/bksprods/kits/kv-k4700U.htm
http://www.audioxpress.com/bksprods/kits/kv-k4701.htm
I'm thinking of using item #KV-K4700U for my ZEN amp or BOSOZ pre-amp myself. What do you guys think?

 

[Lisandro_P]

Rod Elliots' Project 33

Great project. I built one with minor mods and works flawlessly.

 

[palesha]

Dear Lisandro_P,
Can u let us know what modification u have carried on the circuit as mentioned?
Thanks
Mahendra Palesha

 

[Lisandro_P]

Well, for starters i used one circuit for each channel instead of a single one driving the two relays at once. On the ac detector i used two 22uF polarized electros back-to-back in series, bypassed with 1uF multylayer instead of the 10uf NP; used a 12v zenner instead of the 24v ones for the back-emf protection; added two yellow leds to indicate when the channels are muted and the ability to mute the amp with a switch.