Building an A/B box

[Nytephantom]

Simple yet stupid question. I'm building an A/B box as my first project. I have a stereo jack for the input jack. I'm using a dpdt switch. What do I do with the third 'leg' of the stereo jack? Can I just leave it unattached?

[Paul Marossy]

You can omit that third leg if you don't plan on using it to switch the power on/off for an LED indicator.

[peperoni]

The third "leg" is used when connecting a 9v battery to the pedal. I makes a connection so that the battery will only be in use when a INPUT jack in inserted.(hope I made myself clear)