@fanch35 Hello Fanch35,
The adapter I use is the Promate mediaBridge-i. It is more or less a lightning camera adapter with lightning power in and an additional headphone jack.
The Y-cable is an old external HDD cable which has a USB A plug for data, an additional USB A plug for additional power and a Mini USB on the other end of the cable that plugs into the Sylphyo.
The mediaBridge-i provides a USB Audio device for the headphones that you can select as output in audiobus.
Hope it helps.