I misplaced my charger, and I don't remember what I can change and what I can't. The DAC/Amp says 12V DC and shows the polarity. That means 12V, right? I can't use a 15V charger on it? I can use higher amperage, but the voltage has to be correct, right? 'cause the charger I thought I had for it says 15V, but the connector is correct and the polarity is correct. But it could well be for something else, like an external hard drive.