Say I want to play music all day from my iPad. I have 3 possible scenarios I'm thinking. 1: I play the music through the iPad's own speaker. 2: I plug in a pair of small headphones into the iPad's jack socket and listen to the music. 3: I plug a cable from this same headphone jack into the back of an Amp with it's own power supply and speakers. Do you think option 3 would use the least amount of iPad battery?