The Tensor may be drawing more power than your power supply can deliver.  The Tensor requires 250 mA of current and we recommend an isolated power supply.

Note that some multi-pedal supplies are rated at 100 mA except for a couple of high-current outputs.  For example, on the Voodoo Labs Pedal Power 2+ you need to use the L5 outputs (5 & 6) with the DIP switch set to NORMAL.

Other multi-pedal power supplies share current across multiple outputs.  Examples are the T-Rex Fuel Tank and the MXR DC Brick.  You need to make sure the total current required for all connected pedals is within the power supply's limits.  While troubleshooting, you can disconnect one or more pedals to see if the problem goes away.

See this article for information about specific power supplies.