For OB.1, we recommend a 9V battery (included inside OB.1) or any 9VDC center-negative power supply (not included). Some switching supply adapters (1 Spot) have been found to be a bit noisy with OB.1 and are not recommended. Our own Ojai and Zuma power supplies work well without additional noise in the audio.
OB.1 consumes less than 20mA of current.
For further information, please see our blog post on powering your effect pedals at the following link:
Gear Guide: Using the Right Power Supply for your Strymon Pedal