Auto power-on signal sensing circuit

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Slanski62

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Joined 2006
I recently bought a Parasound amp with a signal-sensing automatic power turn on function. I have become thoroughly spoiled by it, I must admit. The problem is that I now want to use a DAC between the signal and the amp. Of course, the DAC must be turned on the old fashioned way.

Does anyone have knowledge of how an auto turn-on feature could be added to the DAC? Any information is much appreciated.

Steve
 
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cliffforrest

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Joined 2004
maczrool said:
I've never made one, but perhaps using a microcrontroller with ADC and a relay this could be done. The micro would sample the signal input and once some programmed threshold is met, it would trigger a relay circuit.

Stu
Click to expand...

Somewhat overkill there :D

A bridge rectifier, long time constant R / C network and a transistir driven relay is all that is needed.
 
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leaseba

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Joined 2007
Hello, I am interested in this circuit for my active subwoofer , I do it myself but I do not understand very well how is the PCB itself and conexciones , is it your project , but you could help me or give me the PCB the same so what I armo on my own . I thank you .
 

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CharlieLaub

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audio.claub.net
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cliffforrest said:
Somewhat overkill there :D

A bridge rectifier, long time constant R / C network and a transistir driven relay is all that is needed.
Click to expand...

OK and how would that work, exactly? The OP is talking about (from what I can tell) LINE LEVEL voltages. The presence of music on the line causes the equipment to turn on. The drop in the bridge will pretty much kill all of the line level voltage. Even without that there is no power to drive a relay.

Maybe you were thinking of something else alltogether?
 
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CharlieLaub

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audio.claub.net
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You can get some ideas for a circuit here:
Project 38

The earlier idea using an Arduino plus a relay board is a pretty good one if you ask me... because audio is bipolar and the Arduinio inputs are unipolar you will need to couple the audio signal into a 2.5V level (or similar) "ground" reference within the 0-5V range of the Arduino.

Whatever it is, it must be powered up and constantly sensing the line for signal.
 
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