The supply adapter is a good transformerless design with a balanced output.
Inside is a Schoeps-style single ended to differential/balanced stage (BJT phase splitter, not JFET, since the JFET for lavaliers is already inside the capsule), followed by one BJT emitter follower for each side of the balanced signal (the balanced output is transistor-based).
May be adapted for other types of microphones by rewiring the 3.5mm connector and/or replacing some resistors. I have changed one to the Sony UWP pinout so I can use with my existing lavalier microphones (all wired for Sony UWP transmitters) into a wired XLR interface.