Active direct box Mackie MDB-1A Black Bass guitar Guitar Synthesizer

The Mackie MDB-1A is an active direct box designed for bass guitar, electric guitar and synthesizer use. It delivers a wide frequency response from 20 to 20,000 Hz and provides an input impedance of 330 kΩ with an output impedance of 150 Ω. The unit accepts phantom power in the 24–48 V range, and its compact steel chassis (86 mm × 147 mm × 38 mm) is built to withstand stage and studio use. The MDB-1A is part of a series of DI boxes that prioritise transparent signal transfer and low noise for reliable direct connections to mixers and audio interfaces.

Advantages

The MDB-1A offers high input impedance suitable for passive and active pickups, preserving instrument tone and dynamics. Its active circuitry provides increased headroom for high-output instruments while maintaining low noise and clear signal transmission. The rugged metal construction and impact-resistant design make it suitable for frequent transport and live use. Compact dimensions allow easy placement on pedalboards or in rack cases without occupying significant space.

Suitable for

• Bass guitar direct-to-mixer or audio interface connection
• Electric guitar with passive or active pickups
• Hardware synthesizers and electronic instruments
• Stage and studio DI needs where low noise and fidelity are required

Key specifications

• Frequency range: 20 – 20,000 Hz
• Input impedance: 330,000 Ω
• Output impedance: 150 Ω
• Phantom power range: 24–48 V
• Chassis dimensions: 86 mm (W) × 147 mm (D) × 38 mm (H)
• Active direct box topology for increased headroom and low noise
• Durable steel construction with impact-resistant corners

How to use

Connect the instrument output (bass, guitar or synth) to the input jack of the MDB-1A. Use a balanced XLR output from the direct box to feed a mixing console or audio interface. Ensure phantom power in the 24–48 V range is available if required by the unit; the MDB-1A uses active circuitry that can be powered via phantom. Place the unit on a pedalboard, stage floor or near the instrument; its compact size allows flexible positioning. Verify signal levels at the mixer to avoid clipping and adjust instrument volume or mixer gain as needed.

Usage recommendations

For best results, use shielded instrument cables and enable phantom power on the mixer only when required. When connecting high-output pickups or active electronics, monitor headroom and reduce instrument output if necessary. The MDB-1A is designed to preserve the natural tone of your instrument—keep EQ and processing minimal at the DI stage and apply further shaping on the console or in the DAW.