What's that black Fiio box connected straight into your iPhone? I have an old iPod with a busted headphone jack and something like that could make it useable again. Does that box only produce a line out level for use with amps or does the iPods volume control still work?
That is the Fiio L11 connector. It has a USB input and a 3.5mm out. So you can sync/charge with this connector and also have audio line out for amps.