Power supply

The device that provides direct current to pedals, either as a battery substitute or as a multi-output isolated unit.

Pedals vary in their appetite, and this is the usual source of trouble on a board: a digital pedal may draw several times what an analogue one does, and a supply that is fine for six analogue pedals will sag or produce noise with one digital unit added. Outputs must also match polarity and voltage, and most pedals expect centre-negative nine volts, though some want twelve or eighteen. Properly isolated outputs prevent one pedal's noise from reaching the others through a shared ground.

Example: a high-pitched whine that appears when a digital reverb is added to a daisy chain usually disappears with an isolated supply.

Power supply

See also