Active Direct Injection Box - 

D10A is an active direct box with transformer and requires the phantom power to work. The advantage of a transformer is the possibility to avoid any electrical connection between the sound source and the mixer. This provides two huge benefits: with no electrical path, ground loops are eliminated and the cancellation of common-mode noise, like hum, is possible. The advantage of active instead of passive DIBOX is null insertion loss and less output hum and noise.