The power adapter that comes with the unit should fit the power plug of the pedal. If you are not able to use the 9V power jack, please open a support ticket at: https://help.positivegrid.com/hc/en-us/requests/new and provide us the serial number.
Serial number format: PDxPBPOP10xx
Also, there are 2 different batches for BIAS Pedal Distortion that comes with different power plug size, please refer to the information below:
BIAS Pedal Distortion Batch 1: 9V DC/negative tip required/2.5mm power plug/270mA.
BIAS Pedal Distortion Batch 2: 9V DC/negative tip required/2.1mm power plug/270mA.
BIAS Pedal Delay/Modulation: 9V DC/negative tip required/2.1mm power plug/270mA.