I bought this:

https://www.aircraftspruce.com/catalog/pspages/pilotUSA32.php

3 years ago to power a bose X that only had the lemo plug. It works great. If you want to add bluetooth you could get this instead:
https://www.aircraftspruce.com/pages/ps/head_adapters_music/blulink.php

N8395M 1970 A150K
The Carolina Swampfoxes founding member
I've landed my Aerobat in the following states:
[Linked Image from visitedstatesmap.com]