Mackie MDB-1P Passive Direct Box DI Box

The MDB-1P is a passive direct box that converts an unbalanced 1/4" signal to a balanced XLR output so it can travel a long cable run to the mixer without picking up hum. Because it is passive, there is nothing to power: no phantom power, no battery, no adapter. Plug in and go.

It is a natural match for acoustic guitars with piezo pickups and for keyboards, where a 140k ohm input impedance and a 350:1 impedance ratio keep the source loaded properly and the tone intact. A -15dB pad handles line-level sources, such as a keyboard output or a mixer feed, without distortion. The 1/4" thru output lets you split the signal to a stage amp while the XLR runs to front of house, and the ground lift switch cuts buzz caused by ground loops between the stage and the board.

The numbers back up the sound: 20 Hz to 20 kHz frequency response, 128 dB of dynamic range, and 0.002% THD from 1000 Hz. It stays quiet and neutral, so your rig sounds the same at the console as it does onstage.

Construction follows the same pattern as the rest of the MDB Series: thick steel chassis, impact-resistant corners, and long-wearing jacks. At 0.8 lb and 1.5" x 3.4" x 5.8", it lives easily in a gig bag, pedalboard, or utility drawer. It fits weekend gigs, worship services, rehearsal spaces, and studio sessions where a passive source needs a clean, reliable path to the mixer.