Crybaby power adaptor

[Dom]

Hey,

I love this place, and I love learning. I think I'm starting to get to grips with it =D

Anyway, this is my first self designed project. Small, and hardly worth mentioning, but hey!

I'm planning on wiring a DC plug (barrel type) and 9v battery snap to a 2 throw, 4 pole switch. This will allow me to select the input power of either a 9v battery, or a DC input.

After the switch, I'm going to combine the positive from the battery snap with the positive from the DC jack, and vice versa, this then gets wired to another battery snap. This battery snap gets snapped to the one in the wah, so this complete power controller is removerable.


So all I want to know is this:
a) Is this a good idea, or will it kill my wah?
b) Will this put extra drain on the battery?
c) Do i need any other components (ie a diode or two to control the current flow?)

Thanks in advance,
Dom