Kenwood KAC 8104D Manual

The Kenwood KAC 8104D is a high-performance 4-channel car amplifier designed for automotive audio systems. This Class D amplifier delivers 150W x 4 channels at 2 ohms or 100W x 4 channels at 4 ohms, featuring MOSFET power supply, variable high-pass/low-pass filters, bass boost, and speaker-level inputs. Below are key sections covering specifications, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. Wiring Connections 4. Specifications 5. Controls and Settings 6. Input Connections 7. Operation Guide 8. Protection Features 9. Care & Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Class D amplifier circuitry, MOSFET power supply, variable electronic crossover, bass boost control, speaker-level inputs, and protection circuits.

Feature	Description
Power Output	150W x 4 @ 2Ω / 100W x 4 @ 4Ω
MOSFET Power Supply	Efficient switching power supply
Crossover	Variable HPF/LPF (50-200Hz)
Bass Boost	0-12dB @ 50Hz
Input Sensitivity	200mV-4V (RCA) / 0.5V-10V (Speaker)
Speaker Connections	4-channel output terminals
Power Connections	+12V, Ground, Remote
Protection	Thermal, Overload, Short Circuit
Dimensions	10-1/16"W x 2-3/16"H x 9-1/16"D
Fuse Rating	25A x 2

Installation

Select proper mounting location and prepare wiring connections.

Choose mounting location: Well-ventilated area, secure surface.
Power wiring: Connect +12V to battery, ground to chassis, remote to head unit.
Speaker connections: Connect speaker wires to appropriate channels.
Input connections: Connect RCA cables or speaker-level inputs.
Fuse installation: Install appropriate fuses near battery connection.

WARNING! Disconnect battery before installation. Ensure proper ventilation to prevent overheating.

Wiring Connections

Proper wiring is essential for optimal performance and safety.

Power Connection: +12V to battery positive, ground to clean metal chassis point.
Remote Turn-on: Connect to head unit's remote turn-on lead (blue wire).
Speaker Outputs: Connect positive/negative terminals to speakers.
RCA Inputs: Connect to head unit preamp outputs.
Speaker-level Inputs: Alternative connection when RCA outputs unavailable.

CAUTION! Use appropriate gauge wire: 8-gauge for power/ground, 16-gauge for speakers.

Specifications

RMS Power: 150W x 4 @ 2Ω / 100W x 4 @ 4Ω
Max Power: 600W total
THD: 0.08%
Frequency Response: 10Hz-50kHz (+0, -1dB)
Signal-to-Noise: 95dB
Crossover: HPF/LPF 50-200Hz (12dB/octave)
Bass Boost: 0-12dB @ 50Hz
Input Sensitivity: 200mV-4V (RCA), 0.5V-10V (Speaker)
Operating Voltage: 14.4V DC (11-16V range)
Fuse Rating: 25A x 2

Controls and Settings

Access controls via top panel: Input level, crossover, bass boost.

Controls: Input Level, Crossover Frequency, Bass Boost, Crossover Mode (HPF/FLAT/LPF).

Input Level: Adjust to match head unit output (start at minimum, increase until distortion). Crossover: Set frequency (50-200Hz) and mode (HPF for mids/highs, LPF for subs). Bass Boost: Add low-frequency emphasis (0-12dB @ 50Hz). Input Select: Choose between RCA or speaker-level inputs.

Input Connections

RCA inputs or speaker-level inputs available for flexibility.

RCA Inputs: Preferred method - connect to head unit preamp outputs.
Speaker-level Inputs: Use when head unit lacks RCA outputs.
Input Sensitivity: Match input level to head unit output voltage.
Ground Loop Isolation: Use if engine noise present.

Tip: Use high-quality RCA cables and keep separated from power wires.

Operation Guide

Proper setup ensures optimal sound quality and system protection.

Initial Setup: Set all controls to minimum before power on.
Input Level: Play music at 3/4 volume, adjust input level until distortion.
Crossover Settings: Set HPF for front/rear speakers, LPF for subwoofers.
Bass Boost: Use sparingly to avoid distortion and speaker damage.
Balance/Fader: Adjust through head unit controls.
Gain Structure: Ensure proper matching between components.

WARNING! Avoid clipping - distorted signal can damage speakers.

Protection Features

Thermal Protection: Automatically shuts down if overheating detected. Overload Protection: Protects against excessive current draw. Short Circuit Protection: Safeguards against speaker wire shorts. DC Offset Protection: Prevents DC voltage to speakers.

Care & Maintenance

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

CAUTION! Do not block ventilation ports. Keep away from moisture and extreme temperatures.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits. Copyright © Kenwood Corporation. For support, visit www.kenwood.com or contact authorized Kenwood service centers. This device complies with part 15 of FCC rules.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	Wiring/fuse	Check power/ground connections; verify fuses; test remote wire.
No sound	Input/connections	Verify RCA/speaker inputs; check head unit settings; test speakers.
Distortion	Gain settings	Reduce input level; check head unit volume; verify speaker impedance.
Overheating	Ventilation/load	Improve ventilation; check speaker impedance; reduce gain settings.
Protection mode	Short circuit/overload	Check speaker wires for shorts; verify proper impedance; allow cool-down.

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

Service: Contact authorized Kenwood service center; www.kenwood.com