# auto-on and off based on presence of audio signal



## MarkZ (Dec 5, 2005)

My HT speaker runs a gainclone inside that I leave on all the time. Which sucks. So I want it to behave like my PE BASH sub amp, and automatically turn on when it senses a voltage on the RCA input, and turn off when it doesn't sense a voltage after a few (10?) minutes.

I hadn't really thought much about it, but I had considered using a comparator with an adjustable threshold for the auto-sense, and maybe a 555 timer OR a simple cap + shunt R circuit for the timing portion. Have the output of this circuit drive a 110v relay which gates the xformer current.

Then I thought ... there must be something in the car audio realm that does this. I'll spend 10 bucks on a controller of some sort, and power it off a low-current 12v regulator.

Anyone know of such a beast? Or do I have to actually put this thing together.


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## SomeGuy748 (Feb 24, 2010)

This should work. Amazon.com: PAC TR7 Universal. Trigger Module: Automotive

I know it's not $10 but I've used them for this function in cars before.


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