Jensen POWER 400.2 Two-Channel Amplifier User Manual

Introduction

This manual provides detailed instructions for the installation, operation, and maintenance of your Jensen POWER 400.2 Two-Channel Amplifier. Please read this manual thoroughly before attempting installation or operation to ensure proper use and to prevent damage to the unit or your vehicle's audio system.

The Jensen POWER 400.2 is a high-performance two-channel amplifier designed to enhance your audio experience with robust power output and versatile control options.

WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information, please refer to relevant safety guidelines.

Product Features

• Two-channel amplifier design
• MOSFET power supply for efficient operation
• Output Power: 2 x 100W @ 2 ohms, 2 x 75W @ 4 ohms, 1 x 200W @ 4 ohms bridged
• Full range operation capability
• High Pass Filter (HPF): 40Hz - 300Hz @ 12dB/octave
• Low Pass Filter (LPF): 40Hz - 300Hz @ 12dB/octave
• Variable Bass EQ: 0 - 12dB @ 45Hz
• Pass-thru RCAs for system expansion
• LED status indicator (Power/Protect)
• Thermal overload protection
• Integrated 25x1 ATO fusing

Setup and Installation

Proper installation is crucial for optimal performance and safety. It is recommended that installation be performed by a qualified professional.

Mounting the Amplifier

Select a secure, dry location for mounting the amplifier, typically on a vehicle chassis or a sturdy surface. Ensure adequate ventilation around the unit to prevent overheating. The amplifier dimensions are 11 x 11 x 4 inches, and it weighs 6.1 pounds. Use the provided mounting hardware to secure the amplifier firmly.

Image: Top-down view of the Jensen POWER 400.2 Two-Channel Amplifier, showcasing its compact design and the Jensen POWER logo.

Wiring Connections

All wiring should be done with the vehicle's battery disconnected to prevent electrical shorts and damage.

1. Power Input (+12V): Connect a heavy-gauge power cable (typically 8-gauge or larger, depending on system requirements) directly from the vehicle's positive battery terminal to the +12V terminal on the amplifier. An in-line fuse (not supplied, but the amplifier uses a 25A ATO fuse internally) should be installed within 18 inches of the battery.
2. Ground (GND): Connect a heavy-gauge ground cable of the same size as the power cable from the GND terminal on the amplifier to a clean, unpainted metal surface of the vehicle chassis. Ensure a solid electrical connection.
3. Remote Turn-On (REM): Connect a remote turn-on wire from your head unit's remote output to the REM terminal on the amplifier. This wire signals the amplifier to turn on and off with your head unit.
4. Speaker Output: Connect your speakers to the SPEAKER OUTPUT terminals. The amplifier supports 2-channel stereo operation or 1-channel bridged operation. Refer to the 'Operating Instructions' for mode selection. Ensure correct polarity (+ to + and - to -).
5. Line Input (RCA): Connect RCA cables from your head unit's pre-amp outputs to the LINE INPUT (L/R) on the amplifier.
6. Line Output (RCA Pass-Thru): If you are connecting additional amplifiers, use the LINE OUTPUT (L/R) RCAs to pass the audio signal to the next amplifier in the chain.

Image: Close-up view of the Jensen POWER 400.2 Amplifier's power input, remote turn-on, ground terminals, fuse holder, and speaker output terminals. The Power and Protect LED indicators are also visible.

Image: Close-up view of the Jensen POWER 400.2 Amplifier's audio input (Line Input), line output (Line Output), Level (Gain) control, Bass EQ, High Pass Filter (HPF), Low Pass Filter (LPF), X-Over mode switch, and Mono/Stereo mode switch.

Operating Instructions

Once the amplifier is installed and wired, you can adjust its settings for optimal audio performance.

Controls and Indicators

• Level (Gain) Control: Adjusts the input sensitivity of the amplifier to match the output level of your head unit. Start with the control at minimum (MIN) and slowly increase until the desired volume is achieved without distortion. The sensitivity range is 4000mV-5V.
• Bass EQ: Provides a variable bass boost from 0 to 12dB at 45Hz. Use this to enhance low-frequency response. Adjust carefully to avoid distortion.
• HPF (High Pass Filter): When engaged, this filter allows frequencies above the set point (40Hz - 300Hz) to pass through to the speakers, blocking lower frequencies. Useful for protecting smaller speakers from bass overload.
• LPF (Low Pass Filter): When engaged, this filter allows frequencies below the set point (40Hz - 300Hz) to pass through to the speakers, blocking higher frequencies. Typically used for subwoofers.
• X-OVER Mode Switch: Selects the crossover mode:
  • FULL: Full range audio signal passes through, no filtering applied.
  • LPF: Low Pass Filter is active.
  • HPF: High Pass Filter is active.
• MODE Switch (Mono/Stereo): Selects between stereo 2-channel operation or bridged mono 1-channel operation. For bridged mode, ensure your speakers are compatible with the amplifier's bridged output impedance.
• LED Status Indicator:
  • Green (Power): Indicates the amplifier is powered on and operating normally.
  • Red (Protect): Indicates the amplifier has entered protection mode due to an issue (e.g., thermal overload, short circuit, low impedance).

Maintenance

The Jensen POWER 400.2 amplifier requires minimal maintenance to ensure long-term performance.

• Cleaning: Periodically wipe the amplifier's exterior with a soft, dry cloth to remove dust and debris. Do not use harsh chemicals or abrasive cleaners.
• Ventilation: Ensure that the amplifier's cooling fins are free from obstructions to allow for proper heat dissipation.
• Fuse Replacement: The amplifier uses an internal 25A ATO fuse. If the amplifier does not power on and the power LED is off, check the fuse. Always replace with a fuse of the exact same type and rating (25A ATO). Using a fuse with a higher rating can cause severe damage to the amplifier or vehicle's electrical system.

Troubleshooting

If you experience issues with your amplifier, consult the following troubleshooting guide before seeking professional assistance.

• No Power / Power LED Off:
  • Check the main power fuse near the battery.
  • Verify the ground connection is secure and clean.
  • Ensure the remote turn-on wire is connected and receiving +12V from the head unit.
  • Check the internal 25A ATO fuse on the amplifier.
• Protect LED On / No Sound:
  • This indicates the amplifier has entered protection mode.
  • Check speaker wiring for shorts (speaker wire touching chassis or other wires).
  • Verify speaker impedance is within the amplifier's acceptable range (2 ohms stereo, 4 ohms bridged).
  • Ensure adequate ventilation; the amplifier may be overheating. Allow it to cool down.
• No Sound / Power LED On:
  • Check RCA input connections from the head unit.
  • Verify speaker connections are secure and correct.
  • Ensure the head unit is powered on and outputting audio.
  • Adjust the Level (Gain) control.
• Distorted Sound:
  • Reduce the Level (Gain) control.
  • Check for proper grounding.
  • Ensure speaker impedance is correct.
  • Reduce Bass EQ if it's set too high.

Specifications

Warranty and Support

For warranty information and customer support, please refer to the documentation included with your purchase or contact Jensen customer service directly. You may also visit the official Jensen website for the most up-to-date support resources.

When contacting support, please have your amplifier model number (POWER 400.2 or 20379204) and purchase details readily available.