Mackie MDB-1A Active Direct Box DI Box

The MDB-1A is an active direct box that converts an unbalanced 1/4" signal into a balanced XLR feed your mixer or stage snake can carry over long runs without hum or level loss. Active circuitry gives it the headroom for hot outputs from active bass pickups, keyboards, and synth modules, and a -20dB pad keeps things clean when a source runs especially hot.

Connections are simple. The high-impedance 1/4" input takes your signal and the 1/4" thru output passes it on to your stage amp, so you can hear yourself while front of house gets a balanced line. The XLR output has a ground lift switch for killing buzz from ground loops between backline and the board. Low cut trims stage rumble, the polarity switch flips phase when you blend a DI with a mic on the same cabinet, and the merge switch sums a stereo source, such as a keyboard or playback device, to mono on one output.

Performance stays transparent: 20 Hz to 20 kHz frequency response, 90dB signal to noise ratio, 130 dB of dynamic range, and 0.02% THD at 1kHz. Power comes from 48V phantom on your mixer, so there is no wall adapter or battery to manage, with only 4.0mA DC of current draw.

The chassis is thick steel with impact-resistant corners and long-wearing jacks, built to live in a gig bag and get stepped on. At 0.8 lb and 1.5" x 3.4" x 5.8", it fits a pedalboard, accessory pouch, or studio drawer. It suits club stages, houses of worship, rehearsal rooms, and recording sessions.