I picked up a voice modulator/changer from HelicalHyperCom. The unit is great and sounds good... but the cell phone charger battery pack I bought apparently cuts power to the unit after a minute because it's not a constant power draw. Does anyone have a suggestion for a battery pack with decent mAh that is "always on" when powered up? I'm hoping for power in the 9v 5,000 mAh range (or larger amperage).