
What is it?
Whether you’re running just a few pedals or have a mega ’board in action, a decent mains-powered pedalboard power supply with multiple outputs is essential – just plug it into the wall socket and you’re good to go.
However, there may be occasions when you can’t easily plug it into the wall socket and, that’s where Walrus Audio’s latest widget, the Canvas Power USB, comes into play.
This compact converter box enables certain standard pedal power supplies to run from USB power delivery, which could be supplied by a laptop charger, high-powered phone chargers or, for truly portable operation, by a USB PD (Power Delivery) battery pack.
Specs

- PRICE: $179/£169/€199
- ORIGIN: USA
- TYPE: Pedal power supply component
- FEATURES: 24V power supply to a compatible pedal power supply unit, switchable 9/12/18V supply to a single pedal, mountable under a pedalboard
- CONTROLS: Pedal supply voltage switch (9V, 12V, 18V)
- CONNECTIONS: 24V In, 24V Out, USB C input, pedal output
- POWER: This will take power from a brick with 24V output, USB laptop charger or a USB PD battery pack
- DIMENSIONS: 93 (w) x 53 (d) x 25mm (h)
- CONTACT: Walrus Audio
Usability and sounds

The Power USB is part of the Canvas ecosystem and so it’s designed to be used with power supplies in the range, including the Canvas Power 8, which takes power from a 24-volt input, rather than an IEC cable.
It will also work with other manufacturers’ 24-volt EIAJ-compatible supplies, such as the Strymon Ojai – you simply connect it from the Power USB’s 24V Thru to your supply’s 24V In socket using the included EIAJ cable.
The Power USB also has a 24-volt input, so, as well as from USB, it can take its power from Walrus Audio’s mains-powered Canvas Power Brick or a similar unit. It prioritises DC brick power when available, seamlessly switching to USB PD input when no brick is detected.

Consequently, the belt and braces approach to cover all contingencies would be to have all of this mounted on your ’board: the Power USB inserted between a brick and your pedal power supply, with a battery pack connected to the Power USB.
Besides powering another power supply, the unit also has one output to power either a nine-volt, 12-volt or 18-volt pedal, with 500mA of current available at nine volts. This reviewer found this aspect of it particularly convenient in connecting to his desktop phone charger when just wanting to try out single pedals.
Verdict
Verdict: ★★★★☆

Guitar World verdict: When paired with a suitable USB PD battery pack (a minimum of 30 watts is required), the Canvas Power USB could make your pedalboard truly portable with enough power to get you through a gig, functioning as an essential backup if there is any difficulty with onstage socketry. That, along with the ability to power one extra pedal, could make it a very useful addition to your rig.
Hands-on videos
Walrus Audio
Ambient Endeavors
Mark Johnston
- “It’s a bit of an investment, but I think these power supplies will truly go the distance if you let them”: Walrus Audio Canvas Power series review
- This article first appeared in Guitarist. Subscribe and save.