Power
Guitar Pedal Power Supplies: Voltage, Current and Isolation
Power compatibility is electrical, not visual. Match every requirement before the plug reaches the pedal.
Research guide · Updated July 27, 2026Match voltage and polarity exactly
Use the voltage and polarity printed by the manufacturer or in the manual. The common 9-volt center-negative format is not universal. Excess voltage or reversed polarity can damage equipment, and a connector that physically fits proves nothing.
Current is capacity: an output may provide more current than a pedal requires when voltage and polarity match. It must not provide less. Treat unusual AC, center-positive and high-voltage devices as separate cases.
Understand what isolation solves
A truly isolated output has its own electrical separation from the others. Isolation can prevent ground paths and interaction between digital and analog pedals that share power, but the product specification must explicitly establish it.
A daisy chain can be compact for compatible low-draw analog pedals. It becomes a poor diagnostic baseline when noise appears because every pedal shares the same supply path.
Budget outputs, not just watts
Count outputs at the voltages and currents your actual pedals need. Include doubling cables only where the power-supply and pedal manufacturers permit them, and distinguish current-doubling from voltage-doubling cables.
Leave one useful output for a likely addition. Also check inlet voltage for travel, mounting hardware, cable lengths and whether the supply remains serviceable when fixed beneath the board.
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