AK55 HiFi Digital Amplifier User Manual

1. Introduction

The AK55 HiFi Digital Amplifier is a versatile 2.0 channel audio amplifier designed for various applications, including home audio, car audio, parties, and conferences. It features Bluetooth 5.0 connectivity, USB and TF card playback, FM radio, and microphone inputs for karaoke. With a maximum power output of 90W per channel, it delivers clear and powerful sound.

2. Package Contents

Please check the package for the following items:

• 1x AK55 Power Amplifier
• 1x Power Cable (US or EU plug, depending on region)
• 1x Remote Control
• 1x Radio Antenna
• 1x English User Manual

3. Product Overview

3.1 Front Panel Controls

1. Power switch
2. TF card interface
3. USB disk interface
4. Function display
5. BT.Aux.MP3.FM signal input select key
6. Upward play button key
7. Pause/play key
8. Down the play button key
9. Music volume control
10. Microphone plug 2
11. Microphone plug 1
12. MIC volume control
13. Treble adjustment
14. Bass adjustment
15. Karaoke reverberation adjustment (Echo)
16. Microphone delay time adjustment (Delay)

3.2 Rear Panel Connections

1. Right channel AUX input signal (RCA)
2. Left channel AUX input signal (RCA)
3. Right channel speaker output
4. Left channel speaker output
5. Power DC 12V/5A input
6. AC power input AC110-240V/50Hz-60Hz
7. FM antenna

3.3 Remote Control Functions

1. Power key
2. Repeat key
3. Signal input select key
4. Press CH-up (Next Track/Station)
5. Press CH-a downward (Previous Track/Station)
6. EQ in several sound cycle (Equalizer Presets)
7. Upward play button key (Play/Next)
8. Down the play button key (Play/Previous)
9. Pause/play key
10. Volume reduce key
11. Volume add key
12. Repertoire straight constituency (Direct Track Selection)

4. Setup Instructions

1. Connect Speakers

   Connect your passive speakers to the speaker output terminals (3 and 4) on the rear panel. Ensure correct polarity (+ to + and - to -). The amplifier supports speakers with an impedance of 4-16 ohms.

2. Connect Audio Sources

   • AUX Input: Use RCA cables to connect external audio devices (e.g., CD player, TV, computer) to the AUX input jacks (1 and 2) on the rear panel. These are analog inputs.
   • USB/TF Card: Insert a USB flash drive or TF card into the respective interfaces (2 and 3) on the front panel for MP3 playback.
   • Bluetooth: Power on the amplifier and select Bluetooth mode. Pair your Bluetooth-enabled device (e.g., smartphone, tablet) with the amplifier.
   • FM Radio: Connect the provided FM antenna to the FM antenna jack (7) on the rear panel for radio reception.

3. Connect Microphones

   Plug your microphones into the MIC1 (11) or MIC2 (10) input jacks on the front panel for karaoke or public address functions.

4. Power Connection

   Connect the power cable to the AC power input (6) on the rear panel. The amplifier supports AC 110-240V. Alternatively, for car use or specific setups, you can use the DC 12V/5A input (5).

   Important Safety Note: Some users have reported potential galvanic isolation issues when using the 220V AC power input, suggesting it may be safer to use an external 12V DC transformer if available, especially if you experience any electrical sensation on the case. The product is advertised to work with 110V/240V AC, but user experience varies.

5. Operating Instructions

1. Power On/Off

   Press the Power switch (1) on the front panel to turn the amplifier ON or OFF.

2. Select Input Source

   Press the signal input select key (5) on the front panel or the 'Signal input select key' (3) on the remote control to cycle through available input modes: Bluetooth (BT), AUX, MP3 (USB/TF), and FM radio.

3. Adjust Volume

   Rotate the main Volume control (9) on the front panel or use the 'Volume add key' (11) and 'Volume reduce key' (10) on the remote control to adjust the overall sound level.

4. Tone Control

   Use the Treble (13) and Bass (14) knobs on the front panel to adjust the high and low frequencies of the audio output to your preference.

5. Microphone Adjustments

   When microphones are connected, use the MIC Volume control (12) to adjust microphone loudness. The Echo (15) and Delay (16) knobs can be used to add reverberation and delay effects to the microphone audio.

6. Media Playback (USB/TF)

   When a USB drive or TF card is inserted, the amplifier will automatically switch to MP3 mode and begin playback. Use the 'Upward play button key' (6), 'Down the play button key' (8), and 'Pause/play key' (7) on the front panel, or corresponding buttons on the remote, to control playback.

7. FM Radio Operation

   In FM mode, use the channel up/down buttons on the remote or front panel to scan for radio stations. Extend the FM antenna for better reception.

6. Specifications

7. Troubleshooting

• No Power: Ensure the power cable is securely connected to both the amplifier and a working power outlet. If using DC 12V, verify the power supply is correct.
• No Sound: Check all audio connections (speakers, input sources). Ensure the correct input source is selected. Increase the main volume and check individual source volumes.
• Sound Distortion: If sound becomes distorted or "sticky" at higher volumes, bass, or treble settings, try reducing these levels. Ensure speaker impedance matches the amplifier's requirements.
• Poor FM Radio Reception: Extend the FM antenna fully and try repositioning it for better signal. Note that FM reception can be noisy in some environments.
• Bluetooth Connection Issues: Ensure the amplifier is in Bluetooth mode and your device's Bluetooth is enabled and in pairing mode. Keep devices within range.
• Remote Control Not Working: Check the battery in the remote control. Ensure there is a clear line of sight between the remote and the amplifier's IR receiver. Some remote buttons may have limited functionality or be specific to certain modes.
• Humming from Audio Inputs: If a constant hum is present when multiple audio sources are connected to the AUX inputs, it may indicate poor isolation. Try connecting one source at a time or using a ground loop isolator if necessary.

8. User Tips

• Sound Quality: While generally powerful, some users note that the bass can be less deep or "dirty" compared to higher-end systems. Treble and midrange are often well-regarded for the price point.
• Bluetooth Performance: The Bluetooth 5.0 offers good range and quick, uncomplicated connections.
• Power-On Notifications: Be aware that the amplifier may produce loud audio notifications when powered on or when switching modes, which cannot be disabled.
• Microphone Features: The microphone inputs include volume, echo, and delay adjustments, but there is no dedicated balance control for the main audio output.
• Heat Generation: The amplifier generally runs cool with minimal heat generation, even during extended use.
• Power Supply Consideration: If you experience issues or concerns with the 220V AC power input, consider using a reliable external 12V DC power supply for potentially safer and more stable operation.

9. Frequently Asked Questions (FAQ)

• Are the RCA audio inputs analog or digital?
  The RCA audio inputs on the AK55 amplifier are analog.
• Can I connect a subwoofer to this amplifier?
  The AK55 is a 2.0 channel stereo amplifier and does not have a dedicated subwoofer output. You can connect a powered subwoofer via its line-level inputs using the amplifier's AUX output (if available, or by splitting the main audio source) or connect a passive subwoofer to the speaker terminals if its impedance matches and your speakers are wired in parallel, but this is not recommended without proper knowledge of audio wiring.
• Does this amplifier support Wi-Fi, 5.1 surround sound, optical, or HDMI connections?
  No, the AK55 amplifier is a basic 2.0 channel stereo amplifier. It does not feature Wi-Fi, 5.1 surround sound processing, optical, or HDMI inputs/outputs.

10. Maintenance

• Cleaning: Use a soft, dry cloth to clean the exterior of the amplifier. Do not use liquid cleaners or solvents.
• Ventilation: Ensure the amplifier has adequate ventilation. Do not block the ventilation openings on the top or sides of the unit.
• Storage: When not in use for extended periods, store the amplifier in a cool, dry place away from direct sunlight and extreme temperatures.
• Power Disconnection: Always disconnect the power cable from the wall outlet before performing any maintenance or if the unit will be unused for a long time.

11. Warranty and Support

For warranty information, technical support, or service inquiries, please refer to the seller's specific policies or contact the point of purchase. Keep your purchase receipt as proof of purchase.

A PDF version of the user manual may be available for download from the seller or manufacturer's website. (Reference: View User Manual (PDF))