I used to have portable players, dacs, battery packs etc for my on the go listening needs.
Now it's only one....my Iphone 6, nothing else.
I got the Lightning to USB 3 Camera Adapter which has both a USB port and a lightning port
so you can charge your phone while you are playing audio, well worth the 10 extra dollars to
get the extra charging port.
I plug my Dragonfly USB DAC-Headphone Amp into the USB port and i'm ready to listen.
I picked the cheaper Dragonfly Black because it has an analog volume control which better
suits my Shure 530 earbuds. The more expensive Dragonfly Red can power full size headphones like my Senn 650's
Having so many files in flac format and being tired of converting to ALAC, i got IOS FLAC Player APP
This can transfer over WIFi flacs from your computer to your phone.
I also use JRiver Media Center to stream flacs to my phone.http://www.audioquest.com/dragonfly-series/http://www.apple.com/shop/product/MK0W2AM/A/lightning-to-usb-3-camera-adapterhttps://itunes.apple.com/us/app/flac-player/id390532592?mt=8