KEBIDU AK45 Bluetooth Audio Amplifier User Manual

1. Introduction

Thank you for purchasing the KEBIDU AK45 Bluetooth Audio Amplifier. This device is designed to provide high-quality stereo audio for your home, car, or karaoke setup. It features multiple input options including Bluetooth, USB, SD card, RCA, and microphone inputs, along with FM radio functionality. Please read this manual carefully before using the amplifier to ensure proper operation and to maximize your audio experience.

2. Safety Information

• Do not expose this appliance to rain or moisture.
• Do not open the casing. There are no user-serviceable parts inside. Refer all servicing to qualified personnel.
• Ensure proper ventilation around the unit. Do not block any ventilation openings.
• Use only the specified power adapter (AC100-240V or DC 12V/5A).
• Keep the unit away from direct sunlight, heat sources, and strong magnetic fields.
• Before making any connections, ensure the amplifier is turned off and unplugged from the power source.

3. Package Contents

Please check the box for the following items:

• KEBIDU AK45 Power Amplifier x 1
• Remote Control x 1
• Power Cord x 1
• User Manual x 1 (This document)
• Radio Antenna x 1

4. Product Overview

4.1 Front Panel Description

The front panel provides controls for power, audio adjustments, input selection, and media playback.

Image: Front view of the AK45 amplifier, highlighting its various input and control features.

1. Power Switch: Toggles the amplifier ON/OFF.
2. SD Card Socket: Insert an SD/MMC card for MP3 playback.
3. Treble Adjustment Knob: Adjusts the high-frequency audio level (-12 to +12).
4. USB Socket: Insert a USB drive for MP3 playback.
5. BASS Control Knob: Adjusts the low-frequency audio level (-12 to +12).
6. Function Display Window: Shows current mode, track number, or FM frequency.
7. Microphone Volume Control (MIC/VOL): Adjusts the volume for connected microphones.
8. Microphone 1 Input Jack (MIC1): Connect your first microphone.
9. Microphone 2 Input Jack (MIC2): Connect your second microphone.
10. Volume Adjustment Knob: Main control for overall audio output volume (MIN to MAX).
11. MP3 Function Buttons:
    • MODE: Switches between input sources (Bluetooth, USB, SD, FM, AUX).
    • ◀◀ (Previous): Selects the previous song/track or tunes down FM frequency.
    • ▶▶ (Next): Selects the next song/track or tunes up FM frequency.
    • ▶‖ (Play/Pause): Plays or pauses MP3 playback. In FM mode, press to auto-search stations.
    • ↺ (Repeat): Toggles repeat mode (single track or all tracks).

4.2 Rear Panel Description

The rear panel houses all the input and output connections for speakers, audio sources, and power.

Image: Detailed diagram of the amplifier's rear panel connections.

1. FM.ANT (Radio Antenna): Connect the included FM antenna for radio reception.
2. AUDIO INPUT (R/L): RCA jacks for connecting external audio sources (e.g., CD player, DVD player, TV).
3. SPEAKERS OUTPUT (RCH/LCH): Terminals for connecting passive speakers (4-16 ohms impedance).
4. DC INPUT (DC12V/5A): Input for 12V DC power supply.
5. AC POWER INPUT (AC100-240V): Input for AC mains power using the provided power cord.

5. Setup

5.1 Speaker Connection

Proper speaker connection is crucial for optimal sound quality and to prevent damage to the amplifier or speakers. The AK45 supports passive speakers with an impedance of 4-16 ohms.

Image: Rear panel view showing speaker output terminals.

1. Identify Polarity: Speakers typically have red (+) and black (-) terminals. Speaker wires also usually have markings (e.g., a stripe, ribbing, or text) to distinguish polarity.
2. Prepare Speaker Wires: Strip about 1 cm (0.4 inches) of insulation from the ends of your speaker wires. Twist the bare strands tightly to prevent stray wires.
3. Connect to Amplifier: Press down on the speaker terminal clips on the amplifier's rear panel. Insert the red (+) wire into the red terminal (RCH+) and the black (-) wire into the black terminal (RCH-) for the right channel. Repeat for the left channel (LCH+ and LCH-). Ensure no bare wires touch each other or the amplifier chassis.
4. Connect to Speakers: Connect the other end of the speaker wires to the corresponding terminals on your passive speakers (red to red, black to black).
5. Important Notes:
   • Do not reverse polarity (connecting + to - and - to +), as this will result in poor sound quality (lack of bass, poor stereo imaging).
   • Ensure speaker impedance matches the amplifier's range (4-16 ohms).
   • Only connect two speakers (one per channel). Do not connect more than one set of speakers in parallel.
   • Speaker wire should be at least 0.3 square millimeters and ideally no longer than 10 meters for best performance.

5.2 Power Connection

The AK45 amplifier supports both AC mains power and DC 12V power.

1. AC Power: Connect the provided power cord to the AC POWER INPUT on the rear panel and then plug it into a standard wall outlet (AC100-240V).
2. DC Power: Alternatively, for portable use or in a car, connect a DC 12V/5A power supply (not included) to the DC INPUT jack.
3. Caution: Do not use both AC and DC power simultaneously.

5.3 FM Antenna Connection

For optimal FM radio reception, connect the included radio antenna to the FM.ANT jack on the rear panel. Extend the antenna fully and position it for the best signal.

6. Operating Instructions

6.1 Basic Operation

1. Power On/Off: Press the POWER switch on the front panel to turn the amplifier ON or OFF.
2. Volume Control: Rotate the main VOLUME knob to adjust the overall sound level. Start with a low volume and gradually increase it.
3. Tone Controls: Use the TREBLE and BASS knobs to fine-tune the high and low frequencies to your preference.

6.2 Bluetooth Connection

Connect your smartphone or other Bluetooth-enabled device to the AK45 amplifier wirelessly.

1. Select Bluetooth Mode: Press the MODE button on the front panel (or remote) until