Using wall wart and battery at same time

[Craig V]

Hi,

This is probably simple, but I searched the archives and didn't find anything.

On some pedals, I would like to install a 9V jack to use with a wall wart.  But I always keep a battery inside in case there's no way to get power to my board at a gig.

My question is, will the battery wear down if the wall wart is being used?  How would I make the pedal so it uses only the wall wart and leaves the battery unused?

Thank you.

[petemoore]

Having no idea, and never having tried it...aren't those switched DC jacks represented in the schematics that have them?
 I'm guessing when the DC plug is 'in' the jack, one of the battery connections is lifted...

[Peter Snowberg]

The jack for the wall-wart has a switch in it that is closed when nothing is plugged into the jack. That way the battery is connected when the jack is not, and when the jack is plugged in, the battery gets disconnected just like you're not using it at all.

The typical jack has three terminals. The one that goes to the center post gets connected to the battery ground and the effect ground. Out of the other two, one connects to the sleeve of the jack and goes to the effect power input, and the other is the switch contact which goes to the battery.

[Craig V]

Thanks guys.  I can't believe it was that simple.  It's kind of how most stereo input jacks are wired to the battery.

Thanks again.