From the FAQ: -What voltage does the DC jack on the back of the unit support. Anything between 6V and 12V should be fine. The device draws about 60ma of power, so you won't need anything too powerful. Please note that the device uses the BOSS style of DC jack wiring, where the center pin is negativ...

I understand that a 9v DC power supply is suggested for external power...however, I can't find anywhere that shows what the polarity is supposed to be. It's not printed by the jack on the enclosure, and I don't see it anywhere in the manual either??? So, is the center pin on the DC jack positive or ...