You could always run your OD2 off a 9V battery. It only draws about 5mA of current, so a typical alkaline 9V battery should last somewhere around 80 - 100 hours of use. If you pony up for one of those lithium "ultra" 9V's, you should get somewhere between 200 - 250 hours. Just remember to take the cable out of the input jack (which disconnects the battery ground) between uses. Just sayin'....