Awhile ago I saw someone asking adding an +18V inverter to a board and the differences it made in some pedals, as well as what they need to do and worry about. Since there are more then a few people who have added an +18V inverter on a switch so they can switch between +9V and +18V, so I thought to myself, why not just whip up a quick layout to show how to do it for those that do not know.
Here’s two that use an NE555 Chip
Here’s two based on the 7660s/1044, based on the voltage doubler section of the madbean road rage voltage doubler section. schematic
Even though you can just run the +9V from the DC jack to SW1 and run that to the power in on the board, I don’t like having multiple wires on a single lug of a switch so I made it so that you grab it form the board instead.