MACKIE HM-400 - 4-Channel Rackmount Headphone Amplifier

MACKIE HM-400 – 4-Channel Rack Headphone Amplifier

The Mackie HM-400 is a 19″, 1U professional headphone amplifier offering 4 independent channels with a total of 12 headphone outputs. Designed “Built-Like-A-Tank™” for intensive use in the studio, live, houses of worship, and rehearsal rooms, it features stereo L/R main inputs with level controls and gateway outputs, plus an auxiliary input per channel with Main/Aux mix control. Each channel features a two-band EQ (Bass and Treble), Mute and Stereo/2-Ch switches, and 7-segment LED meters for precise level monitoring. Its high-fidelity analog circuitry ensures a frequency response of 20 Hz–20 kHz ±1 dB and total harmonic distortion less than 0.01%.

Main features

• Headphone Channels: 4× independent, 3 1/4″ outputs per channel (12 total outputs).
• Main inputs: Stereo L/R (XLR + 1/4″ TRS) with level control and output gateway.
• Auxiliary Inputs: 1× 1/4″ TRS per channel with Main/Aux balance control.
• Channel EQ: Adjustable bass and treble to tailor the sound to each listener.
• Switches: Mute and Stereo/2-Ch mode on each channel for mixing flexibility.
• LED Measurement: 7-segment indicators on each channel and on the main signal for quick visual check.
• Construction: 1U “Built-Like-A-Tank™” metal chassis for maximum durability.

User benefits

• Custom Mixes: Each musician or engineer has their own channel and outputs without interfering with each other.
• Studio Quality: High-fidelity analog circuitry with low noise (–66 dB) and THD < 0.01% ensures clean audio.
• Detailed Control: Dedicated EQ and switches per channel allow quick adjustments during recording or live.
• Precise Monitoring: 7-segment LED meters provide immediate visual feedback of levels.
• Professional installation: Standard 1U rack format and XLR/TRS connections make it easy to integrate into any system.

Use cases

• Monitoring systems in multitrack recording studios.
• Live mix distribution for musicians and sound engineers.
• Rehearsal rooms and houses of worship where multiple users require independent mixes.
• Educational and broadcast environments with simultaneous listening needs.

Frequently Asked Questions

• How many headphone outputs does it offer? 12 outputs in total (3 per channel).
• Can I adjust the bass and treble per channel? Yes; each channel has a two-band EQ.
• What type of meters does it include? 7-segment LEDs per channel and a Main meter.
• Does it support high-impedance headphones? Yes; the 550 mW @ 47 Ω headphone output supports a wide variety of models.

Description for projects

Mackie HM-400 1U rack amplifier with 4 independent channels, 12 headphone outputs, Main L/R inputs with level and passthrough, aux per channel with balance, bass and treble EQ, Mute/Stereo switches, 7-segment LED meters and metal chassis.