DigiTech HardWire V-10 Owner's Manual page 23

Phone Type Power Jacks
If your pedal has a mini (3.5 mm) phone type power jack, polarity is still something which
needs to be verified. Normal polarity for mini (3.5 mm) phone connectors is tip (center)
positive. Therefore, reversed polarity would be tip (center) negative.
TIP (CENTER) POSITIVE (NORMAL) POLARITY TIP (CENTER) NEGATIVE (REVERSED) POLARITY
If you are unable to gather the required information from the pedal's power adapter, take
a look at the pedal's user guide or contact the pedal manufacturer. Also, if you happen
to have a multi-meter, there are ways of determining the power connector's polarity.
Information on how to perform these tests can be found online.
Once the polarity of the power connector for each pedal is known, enter this information
into the "Pedal Requirements Reference Table" provided on page 22.
17