This article explains what you need to know about how to power UAFX Pedals.
UAFX Power Requirements
Note: Power supply is not included.
UAFX pedals require an isolated 9 volt DC, center negative, 2.1 x 5.5 mm barrel connector (same as standard Boss connectors) power supply, which can provide 400 mA of current. Each UAFX pedal must be connected to a separate power supply, or connected to an isolated power connection from a multi-output power supply.
UAFX Power Recommendations
Any modern high-current pedal board power supply that meets the requirements below will work with UAFX pedals. Manufacturers such as Voodoo Lab, Cioks, Truetone, and Strymon make power supplies that work great with UAFX pedals.
Contact your authorized UA dealer for additional details and recommendations.
Each UAFX pedal requires 400 mA (milliamps) of current. If the supply cannot provide 400 mA of current, your pedal might not operate properly, even if the LEDs and switches seem to be working. It’s OK to connect a supply that can deliver more than 400 mA; the pedal only draws the current it needs, and will not be damaged as long as the supply is 9VDC.
An isolated supply provides power and grounding that is electrically separated, usually by means of a transformer for each connector. If the power connection isn’t isolated, you might hear noise and/or ground loop hum in the pedal signals.
If your power supply has multiple outputs, make sure that each output provides true isolation. Some low-cost supplies have separate connectors but don’t provide true ground and power isolation (the connectors might be internally daisy-chained instead of electrically isolated).
Be careful to connect your UAFX pedal to 9 volt DC power only. Higher voltages and/or AC power can damage UAFX pedals.
Connect your UAFX pedal to center-negative DC power only. For example, some effects (such as Eventide H9) require center-positive power. Center-positive supplies and/or cables typically (but don’t always) have a red connector tip.
If power to your UAFX pedal is interrupted during operation, processed audio stops. However, your dry audio signal still passes through the pedal. When the pedal is unpowered, and when it’s starting up, the signals are pure analog dry-through from input to output, without buffering or any other circuitry, via mechanical relays.
Frequently Asked Question
What is an isolated power supply and why are you recommending it?
An isolated power supply has a power input that is electrically independent from its power output, and with multi-output supplies, the outputs are also electrically independent from each other. We recommend using isolated power to prevent ground loops and other noise issues. You can use a dedicated power supply for each pedal on your pedal board, but this is often both space-consuming and inconvenient.
The best solution is to use a dedicated multi-output pedal power supply, but this is where isolation matters. Some cheaper multi-output power supplies have one power input that is simply cascaded to multiple outputs without any isolation, which is a common cause of noise issues. When buying a multiple output power supply, one should make sure that each output is individually isolated.