Mackie HM-400 Rack-Mountable, 4-Channel Headphone Amplifier

4-Channel Rackmount Headphone Amplifier

The Mackie HM-400 is a rack-mountable, 4-channel headphone amplifier designed to provide versatile headphone amplification for artists, musicians, and engineers monitoring through headphones in live stage applications and home, project, commercial, and mobile-recording studios. It features a stereo main output via XLR and 1/4" jacks and twelve 1/4" TRS stereo headphone outputs-three per channel-fed by a customizable blend of inputs.

One stereo main input via XLR and 1/4" jacks can be mixed with a per-channel 1/4" stereo aux input. Each channel offers 2-band EQ for quick tone shaping, stereo balance or main/aux input mix control, and output level adjustments. Also on each channel are switches for muting left and/or right signals and operating in stereo or mono. 7-segment LED meters display main input and per-channel output levels.

The HM-400 ships with an IEC power cable and occupies 1 RU in a standard 19" rack.

Features:

• Distribute signal to up to twelve pairs of headphones
• Occupies 1 RU
• One stereo main input via XLR or 1/4" jacks
• One 1/4" stereo aux input per channel
• One stereo main output via XLR or 1/4" jacks
• Three 1/4" headphone outputs—one on the front panel and two on the rear—per channel fed by an output level control
• 2-band EQ per channel for quick treble and bass adjustments
• Per-channel Balance knob allows control of left/right level balance or aux/main input mix
• Switches on each channel for L/R mute and St/2-Ch (stereo/mono) mode
• 7-segment LED metering for input and each output channel
• Heavy-gauge steel chassis for rugged durability

Specifications:

• Number of Channels: 4
• Input Connections: 2x XLR 3-pin balanced (one stereo pair)
• 2x 1/4" TRS balanced (one stereo pair, also accepts 1/4" TS unbalanced)
• 1x 1/4" TRS stereo unbalanced for main input
• 4x 1/4" TRS stereo unbalanced for aux inputs
• Output Connectors: 2x XLR 3-pin balanced (one stereo pair)
• 2x 1/4" TRS balanced (one stereo pair, also accepts 1/4" TS unbalanced)
• 12x 1/4" TRS stereo unbalanced headphone outputs
• Maximum Input Level: Main Input: +15 dBu
• Aux Input: +20 dBu
• Maximum Output Level: Headphone Outputs: 550 mW per channel at 47 Ohms (+21 dBu)
• Input Impedance: Main Input: 20 kOhms balanced, 10 kOhms unbalanced
• Aux Input: 10 kOhms unbalanced
• Output Impedance: Headphone Outputs: 3 Ohms unbalanced
• Gain Range: Main Input: -66 to +18 dBu
• Function Controls: Power on/off
• Main level knob
• L/R mute switches per channel
• Stereo/2-Ch switches per channel
• 2-band EQ per channel
• Balance knob per channel
• Output knob per channel
• Frequency Response: 20 Hz to 20 kHz (±1 dB)
• THD: <0.01% (+4 dBu, 1 kHz, unity gain)
• Noise: -66 dB
• CMRR: Main Input: >42 dB at 1 kHz
• Display: 1x input level meter
• 4x output level meters
• Power Requirement: 100 to 120 VAC, 50/60 Hz, 24 W
• 220 to 240 VAC, 50/60 Hz, 24 W
• Power Connector: 1x 3-pin IEC male, 250 VAC, 10 A
• Construction Material: Heavy-gauge steel chassis
• Dimensions (Hx Wx D): 1.8x 19.0x 8.8" / 46x 483x 224 mm
• Weight: 8 lb / 3.6 kg