The Mackie MDB-1A is an active direct box designed to connect a single instrument such as a guitar, bass, or keyboard to a microphone preamp for musicians and audio engineers in recording sessions, houses of worship, and live stage applications. It converts a high-impedance, instrument-level signal via its 1/4" TS unbalanced input to a low-impedance, mic-level output via its balanced XLR 3-pin jack. A 1/4" thru jack allows simultaneous connection to an amplifier or pedalboard.


A -20 dB pad reduces the input level to prevent distortion when using a high-gain source, and the ground-lift switch inhibits hum caused by ground loops. Additionally, there are switches for polarity and a 120 Hz high-pass filter. The Merge function allows the Thru jack to be used as a second, simultaneous input. Due to its active design, the MDB-1A operates on phantom power. A sturdy steel chassis enables confident use in the studio or on the road.

MPN: MDB-1A
UPC: 663961054002

• Connect an Instrument to a Mic Input
  
• Converts Unbalanced to Balanced
  
• Converts High Impedance to Low Impedance
  
• 1/4" Unbalanced Input
  
• 1/4" Thru Jack
  
• XLR Balanced Output
  
• Switchable Pad Prevents Overloading
  
• Ground-Lift Switch Minimizes Hum
  
• Merge, Low-Cut, and Polarity Switches
  
• Operates on Phantom Power
  
  
• Connect an instrument such as a guitar, bass, or keyboard to a microphone preamp
  
• Converts a high-impedance, unbalanced 1/4" input to a low-impedance, balanced XLR mic-level output
  
• 1/4" thru jack for routing to an amplifier
  
• -20 dB pad prevents overloading when accepting signal from a loud source
  
• Ground-lift switch minimizes hum
  
• Active design operates on phantom power