Kenwood KAC 8406 Manual

The Kenwood KAC 8406 is a high-performance 4-channel car amplifier designed to deliver exceptional audio quality with 75W RMS per channel at 4 ohms. Features include MOSFET power supply, variable high-pass/low-pass filters, bridged mode operation, speaker level inputs, and comprehensive protection circuits. Below are key sections for installation, specifications, controls, wiring, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. Wiring Connections 4. Specifications 5. Controls and Settings 6. Operation Modes 7. Protection Features 8. Maintenance 9. Regulatory Information 10. Troubleshooting

Features at a Glance

Key components: MOSFET power supply, 4-channel operation, bridged mode capability, variable crossover filters, speaker level inputs.

Feature	Description
Power Output	75W RMS x 4 channels at 4 ohms
MOSFET Power Supply	For efficient power delivery and reliability
Variable Crossover	High-pass and low-pass filter adjustments
Bridged Mode	Combine two channels for higher power output
Speaker Level Inputs	Connect directly to factory head units
Protection Circuits	Thermal, short-circuit, and DC offset protection
Bass Boost	+12dB boost at 50Hz
Input Sensitivity	200mV to 4V adjustable
Frequency Response	10Hz - 50kHz
Signal-to-Noise Ratio	>100dB

Installation

Choose a secure, well-ventilated location in vehicle.

Disconnect negative battery terminal before installation.
Mount amplifier using provided hardware on flat surface.
Ensure adequate ventilation around amplifier.
Route power cable through firewall away from moving parts.
Connect ground wire to clean, bare metal surface.

WARNING! Ensure proper fuse rating and secure all connections to prevent electrical hazards.

Wiring Connections

Proper wiring is essential for optimal performance and safety.

Power Connection: Connect +12V to battery with appropriate fuse.
Ground Connection: Use short, thick wire to chassis ground.
Remote Turn-on: Connect to head unit's remote output.
Speaker Connections: Observe polarity for proper phasing.
RCA Inputs: Use high-quality shielded cables.

CAUTION! Do not run power cables parallel to RCA cables to avoid noise.

Specifications

RMS Power: 75W x 4 @ 4 ohms, 100W x 4 @ 2 ohms
Bridged Power: 200W x 2 @ 4 ohms
THD: 0.08% at rated power
Input Sensitivity: 200mV - 4V adjustable
Crossover Frequency: High-pass: 50-500Hz, Low-pass: 50-500Hz
Bass Boost: 0 to +12dB at 50Hz
Dimensions: 10.2" x 8.1" x 2.2"
Operating Voltage: 14.4V DC (11-16V range)

Controls and Settings

Access controls via front panel adjustments.

Front Panel Controls: Input Level, High-pass Filter, Low-pass Filter, Bass Boost, Bridge Mode Switch.

Input Level: Adjust to match head unit output. Crossover: Set HPF for speakers, LPF for subwoofers. Bass Boost: Use sparingly to avoid distortion. Bridge Mode: Combines channels 1+2 and 3+4 for mono operation.

Operation Modes

Multiple operation modes for different audio setups.

4-Channel Mode: Standard operation for front and rear speakers.
3-Channel Mode: Channels 1-2 for fronts, bridged 3-4 for subwoofer.
Bridged Mode: Maximum power for two speakers or subwoofers.
Bi-Amp Mode: Use crossovers for separate tweeter/midrange driving.

Tip: Always set gains properly to avoid clipping and speaker damage.

Protection Features

Comprehensive protection circuits ensure amplifier longevity.

Thermal Protection: Shuts down if temperature exceeds safe limits
Short-Circuit Protection: Protects against speaker wire shorts
DC Offset Protection: Prevents DC voltage from reaching speakers
Over-Voltage Protection: Guards against voltage spikes
Under-Voltage Protection: Prevents operation below 10V

Maintenance

Keep amplifier clean and free of debris.

CAUTION! Disconnect power before cleaning. Use compressed air to remove dust; avoid liquid cleaners.

Regulatory Information

FCC Part 15: Class B digital device compliant. CE certified for European markets. Copyright © Kenwood Corporation. All trademarks property of their respective owners. For technical support, visit www.kenwood.com or contact 1-800-536-9663.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	Power/ground connections	Check battery connection; verify ground; inspect fuse.
Protection mode	Short circuit/overheating	Check speaker wires for shorts; ensure proper ventilation.
Distorted sound	Gain settings/clipping	Adjust input level; check head unit volume.
No sound from channels	Input connections	Verify RCA connections; check remote turn-on wire.
Engine noise	Ground loop/poor routing	Improve ground connection; reroute RCA cables.

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

Service: 1-800-536-9663; www.kenwood.com