Kenwood KAC 8401 Manual

The Kenwood KAC 8401 is a high-performance car audio amplifier featuring 4-channel output, MOSFET power supply, variable high/low pass filters, bridged operation capability, speaker level inputs, and comprehensive protection circuits. With a maximum power output of 600W and RMS power of 60W x 4 channels at 4 ohms, this amplifier delivers exceptional sound quality for automotive audio systems. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Devices 7. Operation Modes 8. Protection Features 9. Care & Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: 4-channel amplifier, MOSFET power supply, variable crossover network, speaker level inputs, protection circuits.

Feature	Description
MOSFET power supply	For efficient power conversion and thermal stability
Variable high/low pass filters	Adjustable crossover frequencies for optimal sound
Speaker level inputs	Direct connection to factory head units
Bridged operation	Combine channels for higher power output
Protection circuits	Thermal, short-circuit, and DC offset protection
RCA inputs	For line-level audio input
Power/ground terminals	For electrical connections
Gain controls	Adjust input sensitivity for each channel
Crossover controls	Select filter types and frequencies
Bass boost	Enhance low-frequency response

Installation

Unpack and inspect contents. Choose suitable mounting location.

Disconnect vehicle battery: Remove negative terminal for safety.
Mount amplifier: Secure to stable surface with proper ventilation.
Connect power: Run power cable from battery with inline fuse.
Connect ground: Use short, thick cable to clean metal chassis point.
Connect audio inputs: Use RCA cables or speaker level inputs.
Connect speakers: Ensure proper polarity and impedance matching.
Connect remote turn-on: Wire to head unit remote output.

WARNING! Ensure proper fuse rating and secure all connections. Do not mount near heat sources or moving parts.

First-Time Setup

Reconnect battery and power on system; adjust settings gradually.

Set gain controls: Start at minimum, increase until desired volume.
Configure crossovers: Set high/low pass filters based on speaker types.
Adjust bass boost: Use sparingly to avoid distortion.
Test all channels: Verify proper operation of each speaker.
Fine-tune settings: Make minor adjustments for optimal sound quality.

CAUTION! Set gains properly to prevent speaker damage. Allow amplifier to cool between adjustments.

Specifications

Channels: 4
RMS Power: 60W x 4 @ 4 ohms
Max Power: 600W
Frequency Response: 10Hz - 50kHz
Signal-to-Noise Ratio: >100dB
Input Sensitivity: 200mV - 4V
Crossover: Variable 50Hz - 200Hz
Bass Boost: 0-12dB @ 50Hz
Dimensions: Standard amplifier size
Operating Voltage: 14.4V DC

Controls and Settings

Front/Rear gain controls, crossover switches, bass boost, input mode selector.

Controls: Power indicator, protection indicator, gain knobs, crossover frequency controls, bass boost control, input mode switch.

Gain: Adjust input sensitivity (200mV-4V). Crossover: Select HPF/LPF/FLAT, adjust frequency (50-200Hz). Bass Boost: 0-12dB boost at 50Hz. Input Mode: Select stereo or bridged operation.

Connecting Devices

RCA inputs for line-level, speaker level inputs for factory systems, power/ground connections.

Disconnect battery before making connections.
Use proper gauge wiring for power and ground.
Route signal cables away from power wires.
Ensure secure connections at all terminals.
Use appropriate fuse for power cable.

Tip: Keep power and signal cables separated to minimize noise interference.

Operation Modes

Supports stereo, bridged, and multi-channel operation.

Stereo mode: Standard 4-channel operation for front/rear speakers.
Bridged mode: Combine channels for higher power to single speakers.
High-pass filter: Use for small speakers or tweeters.
Low-pass filter: Use for subwoofers.
Full-range: Bypass crossover for full frequency response.

WARNING! Do not bridge channels below recommended impedance. Check speaker compatibility before bridging.

Protection Features

Thermal protection: Automatically reduces output if overheating detected. Short-circuit protection: Cuts output if short circuit occurs. DC offset protection: Prevents DC voltage from reaching speakers.

Care & Maintenance

Keep amplifier clean and dry. Ensure proper ventilation. Check connections periodically for corrosion or looseness.

CAUTION! Do not use chemical cleaners. Keep free of dust and moisture. Ensure adequate airflow around amplifier.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits for automotive use. Copyright © Kenwood Corporation; all rights reserved. For support, visit www.kenwood.com or contact authorized service centers.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	Power/ground connections	Check battery connection, fuse, ground connection.
Protection mode active	Overheating/short circuit	Allow to cool; check speaker wiring for shorts.
Distorted sound	Gain settings/input level	Adjust gain controls; check head unit output.
No sound from channels	Input connections/settings	Verify RCA connections; check input mode setting.
Amplifier overheating	Insufficient ventilation	Improve airflow; check impedance load.

Reset: Disconnect power for 30 seconds to reset protection circuits.

Service: Contact authorized Kenwood service center for repairs.