Kenwood 9104D Manual

The Kenwood 9104D is a high-performance car audio amplifier with advanced digital signal processing, multi-channel output capability, built-in crossover networks, and comprehensive protection circuitry. Designed for automotive use with 12V DC power supply, this amplifier delivers superior sound quality with features like bass boost, variable gain control, thermal protection, and short-circuit protection. 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: Multi-channel amplifier, Remote bass control, Power/Protection indicators, Speaker terminals, RCA inputs, Gain controls.

Feature	Description
Power Output	4 x 50W RMS at 4 ohms
Frequency Response	20Hz - 20kHz
Signal-to-Noise Ratio	>95dB
Crossover Networks	High-pass and low-pass filters
Bass Boost	Variable 0-18dB at 45Hz
Input Sensitivity	200mV - 4V
Remote Turn-on	12V DC trigger input
Thermal Protection	Automatic shutdown at high temperature
Short-Circuit Protection	Automatic circuit protection
Power Supply	12V DC automotive system

Installation

Unpack and inspect contents. Choose appropriate mounting location in vehicle.

Disconnect vehicle battery: Remove negative terminal for safety.
Mount amplifier: Secure to solid surface using provided hardware.
Connect power: Run power cable from battery to amplifier with inline fuse.
Connect ground: Use short, thick cable to clean metal chassis point.
Connect speakers: Use appropriate gauge speaker wire.
Connect audio inputs: Use RCA cables from head unit.
Connect remote turn-on: Wire to head unit remote output.

WARNING! Ensure proper ventilation; do not mount near heat sources. Use correct fuse rating.

First-Time Setup

Reconnect battery and power on system; follow setup procedure.

Set gain controls: Start at minimum, adjust gradually while playing music.
Configure crossover: Set high-pass/low-pass frequencies based on speaker setup.
Adjust bass boost: Set to desired level (start with minimal boost).
Test all channels: Verify proper operation of each speaker output.
Check protection indicators: Ensure no warning lights are illuminated.

CAUTION! Set gains properly to avoid distortion and speaker damage.

Specifications

RMS Power: 4 x 50W @ 4 ohms, 4 x 75W @ 2 ohms
Max Power: 4 x 100W @ 4 ohms
THD: <0.08% at rated power
Input Impedance: 22k ohms
Crossover Frequency: 50Hz - 500Hz (high-pass), 50Hz - 500Hz (low-pass)
Bass Boost Frequency: 45Hz ±10Hz
Operating Voltage: 11-16V DC
Fuse Rating: 25A x 2
Dimensions: 260mm x 180mm x 55mm

Controls and Settings

Access controls via front panel and remote bass controller.

Front Panel: Power indicator, Protection indicator, Gain controls, Crossover frequency controls, Bass boost control.

Gain: Adjust input sensitivity (200mV-4V). Crossover: Select high-pass/low-pass with frequency adjustment. Bass Boost: Variable 0-18dB at 45Hz. Input Mode: Select 2-channel/4-channel input. Remote Bass: Connect optional remote bass level control.

Connecting Devices

RCA inputs for front/rear channels, Speaker outputs, Power/ground/remote connections.

Disconnect battery before making connections.
Use high-quality RCA cables for audio inputs.
Match speaker impedance to amplifier capabilities.
Ensure proper polarity on all connections.
Use appropriate gauge wire for power and speakers.

Tip: Keep power cables separated from audio cables to minimize noise.

Operation Modes

Supports stereo and bridged operation modes.

Stereo Mode: Standard 4-channel operation for front/rear speakers.
Bridged Mode: Combine channels for higher power to single speakers.
Crossover Modes: Full range, high-pass, or low-pass filtering.
Input Modes: 2-channel or 4-channel input selection.
Remote Control: Optional bass level remote adjustment.

WARNING! Do not bridge channels to impedance lower than specified minimum.

Protection Features

Thermal Protection: Automatic shutdown when temperature exceeds safe limits. Short-Circuit Protection: Prevents damage from output shorts. DC Offset Protection: Monitors output for DC voltage. Over-Voltage Protection: Guards against excessive input voltage.

Care & Maintenance

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

CAUTION! Do not use chemicals or water for cleaning. Keep free of dust and debris.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits. CE certified for European markets. Copyright © 2025 Kenwood Corporation; all rights reserved. For technical support, visit www.kenwood.com or contact 1-800-KENWOOD.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	Power connection/fuse	Check battery connection; verify fuse integrity; test remote turn-on wire.
Protection light on	Short circuit/overheat	Check speaker wires for shorts; allow amplifier to cool; verify proper impedance.
No sound	Input connections/settings	Verify RCA connections; check head unit output; adjust gain settings.
Distorted sound	Gain settings/clipping	Reduce gain settings; check input levels; verify speaker compatibility.
Overheating	Insufficient ventilation/load	Improve airflow; check speaker impedance; reduce volume levels.

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

Service: 1-800-KENWOOD; www.kenwood.com