The most simple way to realize a positive and negative power source for the analog computer Confetti is to use two 9V batteries and connect the positive pole of one battery to the negative pole of the other. The red wire is allway the plus and the black one allways minus. This new build connection is the so called common ground. It's marked on the boards as COM. The other two are +9V and -9V. One can use them instead of +12V and -12V. In soldering all three to a three pin connector one gets a nice power supply.

An other possibility would be to build the Confetti003 Power Brick

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