Behringer MICROAMP HA400 Ultra-Compact 4-Channel Stereo Headphone Amplifier

1. Introduction and Overview

The Behringer MICROAMP HA400 is an ultra-compact 4-channel stereo headphone amplifier designed to provide monitoring solutions for multiple users. It allows up to four individuals to listen to a main audio mix simultaneously, with each user having independent control over their headphone volume. This device is ideal for studio recording sessions, rehearsals, or any scenario requiring distributed headphone monitoring.

The HA400 features four high-power stereo amplifiers that maintain high sonic quality even at maximum volume levels. It incorporates ultra-low-noise 4580 operational amplifiers, commonly found in larger audio equipment, ensuring outstanding audio performance.

2. What's in the Box

• Behringer MICROAMP HA400 4-Channel Stereo Headphone Amplifier
• 12V DC Power Adapter
• User Manual (this document)

3. Key Features

• 4 Independent Stereo Channels: Allows up to four pairs of headphones to be connected simultaneously.
• Individual Volume Control: Each headphone output features its own dedicated level control for personalized listening.
• High-Power Amplifiers: Ensures excellent sonic quality and sufficient volume even for high-impedance headphones.
• Ultra-Low-Noise Operation: Utilizes 4580 operational amplifiers for clear audio reproduction.
• Compact Design: Its small footprint makes it suitable for various setups, from home studios to portable applications.
• Dedicated Power Supply: Includes a 12V DC adapter for reliable power.

4. Setup Guide

Follow these steps to set up your Behringer HA400 headphone amplifier:

1. Connect Power: Plug the included 12V DC power adapter into the '12V =' input on the rear panel of the HA400. Connect the other end to a suitable power outlet. The 'ON' LED on the front panel will illuminate.
2. Connect Audio Input: Connect your audio source (e.g., mixer, audio interface, computer headphone output) to the 'INPUT' jack on the rear panel using a 1/4" TRS cable. Ensure the audio source's output level is set appropriately to avoid clipping.
3. Connect Headphones: Plug your headphones into any of the four '1', '2', '3', or '4' output jacks on the front panel. The HA400 supports 1/4" TRS headphone plugs.

Figure 1: Front panel of the Behringer HA400, showing four independent volume controls and headphone outputs.

Figure 2: Rear panel of the Behringer HA400, illustrating the 12V DC power input and the 1/4" TRS audio input.

5. Operating Instructions

Once the HA400 is set up, operating it is straightforward:

1. Power On: Ensure the power adapter is connected and the unit is receiving power. The 'ON' LED on the front panel should be lit.
2. Adjust Input Source Volume: Start with the volume of your audio source (e.g., mixer, interface) at a low level and gradually increase it to a comfortable monitoring level.
3. Adjust Individual Headphone Levels: Use the 'LEVEL 1' through 'LEVEL 4' rotary controls on the front panel to set the desired volume for each connected pair of headphones. Adjust these controls to achieve a clear and comfortable listening experience without distortion.

6. Specifications

7. Troubleshooting

• No Sound:
  • Ensure the 12V DC power adapter is securely connected and the 'ON' LED is lit.
  • Verify that the audio input cable is correctly connected to the 'INPUT' jack and your audio source.
  • Check that your headphones are properly plugged into one of the output jacks.
  • Increase the 'LEVEL' control for the corresponding headphone channel and the volume on your audio source.
• Distorted Sound:
  • Reduce the 'LEVEL' control for the affected headphone channel.
  • Lower the output volume from your audio source.
  • Ensure that the audio signal from your source is not already distorted before reaching the HA400.
• Hum or Buzz:
  • Check all cable connections for secure fit.
  • Ensure you are using high-quality, shielded audio cables.
  • Try connecting the HA400 and your audio source to the same power strip or outlet to minimize ground loop issues.
  • Keep the unit away from strong electromagnetic interference sources.

8. Maintenance

To ensure the longevity and optimal performance of your Behringer HA400, follow these simple maintenance guidelines:

• Cleaning: Use a soft, dry cloth to clean the exterior of the unit. Avoid using abrasive cleaners, solvents, or waxes.
• Environment: Operate and store the device in a clean, dry environment away from extreme temperatures, humidity, and direct sunlight.
• Handling: Handle the unit with care. Avoid dropping it or subjecting it to strong impacts.
• Cables: Regularly check all cables for damage. Replace any frayed or damaged cables to prevent performance issues or safety hazards.

9. Important Safety Information

Please read and adhere to the following safety precautions:

• Power Source: Only use the provided 12V DC power adapter. Using an incorrect power supply may damage the unit and void the warranty.
• Water and Moisture: Do not expose this appliance to rain or moisture. Do not place objects filled with liquids, such as vases, on the apparatus.
• Ventilation: Ensure adequate ventilation around the unit. Do not block any ventilation openings.
• Heat: Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
• Servicing: Do not attempt to service this product yourself. Refer all servicing to qualified service personnel.
• Hearing Protection: Prolonged exposure to high volume levels can cause permanent hearing damage. Always use headphones at a comfortable listening level.

10. Warranty and Support

For warranty information, technical support, or service inquiries, please refer to the official Behringer website or contact your local distributor. Keep your purchase receipt as proof of purchase for any warranty claims.