This little utility board takes up the space of a 9V battery in your pedal and can turn a daisy-chained +9V power supply into a -9V supply for your vintage inspired Germanium pedals. It also handles your LED pull down resistor.
Board artwork
Print size: 1.6 x 0.7 inches at 300dpi
Component layout
IC1 is a 7660 chip (ICL7660SCPAZ CMOS Voltage Converter IC) to convert the power from +9V to -9V.
C1 is part of the inverter circuit and is a 10uF electrolytic, C3 is also part of this circuit and is a 47uF electrolytic.
C2 is a power filter and, in reality, can be anything from 47uF to 100uF just watch the sizing and the orientation.
D1 provides some reverse polarity protection – I like to use 1N4001 for this although the forward voltage drop can be a little high, reducing the power into the pedal by 0.5V-1.0V.
R1 is the pull down resistor for the LED – I like to use a 4K7 here but it’s up to you. The L+ pad goes to the positive side of your LED and the L- takes the negative side of the LED once it’s been routed through your 3PDT switch.
There’s three ground connections on there – I use one to run to the power socket, another one to the pedal circuit ground, and then the other one to the sleeve of my input socket.
The two small holes, one on each side, are pilot holes for mounting screws or PCB standoffs.
