thats a funny way to connect the battery to the circuit via the input jack, I think there is something quite wrong with that diagram, I would suggest bypassing that bit and just connecting the battery to the IC and perhaps use a switch, I think the diagram has badly tried to show that the input jack much have a separate switch on it that closes when a plug is put into is to turn the power on when you plug it into the guitar, just use a "normal" jack and a very normal switch