Timer for amplifier

[vinod chandran]

Hi all,
I need a timer circuit for my sub-woofer amplifier. I used this amp with my PC. But i can't connect the power cord of this amp into my UPS and SMPS. Every time i forget to turn off this amp with my PC. So i need a timer circuit to turn off this amp when there is no audio signal available for more than 3 minutes.
Vinod Chandran

 

[Yoa01]

Wouldn't that be bad if you were to simply not have any audio playing for 3 minutes? You'd have to turn it back on every time. Either way, something like http://cindybob.com/halloween/circuits/timer.jpg would be useful to you. It's a relay switched with a 555. You'd need some kind of voltage generator to trigger the 555 when there is no audio, and set the 555 to not do anything until 3 minutes passed.

As for precisely how to do that, Google might help, or someone else here. I'm an audio guy, sorry mate!

 

[CocaCola]

A simple solution is to use the +5V of a USB port on the computer to drive a relay (best to provide some isolation when doing do) when the computer is on the relay is held closed and the amp is powered up, when the PC shuts off the USB port stops powering the relay and the amp goes off... No delay and no need for any timers, just a quick and dirty hack that drives the relay when the PC is powered up...