18v power options

[brd]

I have built an Over Drive Circuit pedal that is ready for 18v and I’m trying to decide if I should buy an 18v power supply or use a charge pump.

Are there any issues or concerns with using a charge pump to power that circuit at 18v that would make using an 18v power supply a better option?

[wilkie1]

An isolated power supply would provide a quieter voltage to the pedal than a charge pump.  If you use a charge pump, be sure to follow the recommended filter capacitor  values.  You want to do two things:  Filter high frequency noise from the oscillator and provide reserve charge to prevent voltage sag under load.

[brd]

Thanks, that is very helpful Wilkie, There are a couple pedals I want to try this on and I have some extra 1044’s to breadboard a quick test circuit. If it works, I’ll try to build it.

[brd]

Got this finished. It is a quick build from a generic Charge Pump schematic, done on vero board, the orange wire supplies +17.4 volts. I used a piece of Barry’s new Gum Wadz to hold it in place, and as the photo shows, It fits nicely behind and under a foot-switch. I remain agnostic about any benefits to playing this pedal at 18v but the owner likes it.

[wilkie1]

Very neat!  The only concern about using 18V, is the value of other components.  All components should be rated for 1 1/2 times the voltage supplied.  So 16V rated capacitors would not be a good idea.

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