Sony DC-78 Battery Power Unit for ECM Lavalier Microphones

The DC-78 is the power supply that turns a bare-capsule Sony lavalier into a microphone a mixer can use. The ECM-44BC, ECM-77BC, ECM-88BC and ECM-90BC all terminate in Sony's small four-pin connector and carry no electronics of their own; the DC-78 supplies them and presents a standard balanced XLR output at the other end.

It is the piece people forget to order and then cannot shoot without, so it belongs in every kit that carries a BC-type lavalier.