Introduction
Thank you for purchasing the LDZS AV-628BT HiFi Digital Bluetooth Audio Amplifier. This amplifier is designed to provide high-quality audio output for home, automotive, or car speaker systems, featuring 2.1 channel sound, Bluetooth 5.0 connectivity, USB/SD card playback, and microphone inputs for karaoke functions. Please read this manual thoroughly before use to ensure proper operation and to maximize your listening experience.
Safety Information
Please observe the following safety precautions to prevent electric shock, fire, or damage to the unit:
- Ensure the amplifier is connected to the correct power supply (12V or 220V) as indicated on the unit. Incorrect voltage can cause severe damage.
- Do not expose the unit to rain, moisture, or excessive humidity.
- Do not open the amplifier casing. There are no user-serviceable parts inside. Refer all servicing to qualified personnel.
- Place the amplifier on a stable, level surface with adequate ventilation to prevent overheating.
- Keep the unit away from direct sunlight, heat sources, and strong magnetic fields.
- Disconnect the power plug from the wall outlet if the unit is to be left unused for a long period.
- Do not overload the amplifier. Ensure connected speakers match the impedance and power ratings.
Package Contents
The package includes:
- 1 x LDZS AV-628BT Audio Amplifier
- 1 x Power Cable (EU or US Plug, depending on variant)
- 1 x Remote Control
- 1 x User Manual (this document)
Product Overview
Front Panel Functions
The front panel provides access to all primary controls and inputs for easy operation.
Figure 1: Front and Rear Panel Functions
- Power Switch: Turns the unit on/off.
- MIC VOL: Adjusts the volume of the microphones.
- MIC1 / MIC2: 6.5mm standard microphone input jacks.
- M.BASS / M.TREBLE: Adjusts bass and treble for microphone input.
- ECHO / REVERB: Controls the echo and reverb effects for microphones.
- USB Interface: For USB drive playback.
- SD/MMC CARD: For SD/MMC card playback.
- Display Screen: Shows current mode, track information, and volume.
- IR: Infrared receiver for remote control.
- INPUT: Selects audio input source (VCD, CD, LINE, Bluetooth, USB, SD, FM).
- REC: Recording function (for basic recording to USB/SD).
- VOCAL: Vocal cancellation function for karaoke.
- Music Controls: Previous song, Pause/Play, Next song, Mode switching, One-click mute.
- TREBLE / BASS: Adjusts the treble and bass for music playback.
- BALANCE: Adjusts the left/right channel balance.
- MUSIC VOL: Main volume control for music.
- SW.VOL: Subwoofer volume control.
Rear Panel Connections
The rear panel houses all necessary audio input and output connections.
Figure 2: Rear Panel Connections
- AUDIO INPUT (VCD, CD, LINE): RCA stereo audio input jacks for external devices.
- AUDIO OUTPUT: RCA stereo audio output jacks.
- SUBWOOFER OUT: RCA output for connecting an active subwoofer or an amplifier for a passive subwoofer.
- SPEAKER OUT (4-16Ω): Left and Right channel speaker terminals for passive speakers.
- DC POWER INPUT (12V/15A): For 12V power supply (e.g., automotive use).
- FM ANTENNA: Connector for FM radio antenna.
- AC INPUT (220V/50Hz): For standard AC power supply.
Setup
- Placement: Place the amplifier on a flat, stable surface, ensuring adequate space around it for ventilation. Avoid placing it near heat sources or in enclosed spaces.
- Power Connection:
- For Home Use (AC 220V): Connect the provided AC power cable to the "AC INPUT" on the rear panel and then to a wall outlet.
- For Automotive Use (DC 12V): Connect a 12V/15A DC power supply (not included) to the "DC POWER INPUT" on the rear panel. Ensure correct polarity.
WARNING: Do NOT connect both AC and DC power simultaneously. Ensure the correct voltage is used for your region and application.
- Speaker Connection:
- Connect your passive left and right speakers to the "SPEAKER OUT (4-16Ω)" terminals on the rear panel. Ensure correct polarity (+ to + and - to -).
- For subwoofer output, connect the "SUBWOOFER OUT" RCA jack to an active subwoofer or a dedicated subwoofer amplifier.
- Audio Input Connection:
- Connect your audio sources (e.g., CD player, DVD player, TV, computer) to the "AUDIO INPUT" RCA jacks (VCD, CD, LINE) on the rear panel.
- FM Antenna Connection: Connect the FM antenna to the "FM ANTENNA" terminal for radio reception.
- Microphone Connection: If using microphones, plug them into the "MIC1" or "MIC2" 6.5mm jacks on the front panel.
Operating Instructions
- Power On: Press the "POWER" switch on the front panel to turn on the amplifier. The display screen will light up.
- Select Input Source: Press the "INPUT" button on the front panel or remote control to cycle through available input sources (VCD, CD, LINE, Bluetooth, USB, SD, FM).
- Adjust Volume: Rotate the "MUSIC VOL" knob to adjust the main music volume. Use "SW.VOL" for subwoofer volume.
- Tone Control: Use the "TREBLE" and "BASS" knobs to adjust the high and low frequencies of the music. Adjust "BALANCE" for left/right channel output.
Bluetooth Connection
- Select "Bluetooth" as the input source using the "INPUT" button. The display will show "BLUE" or a similar indicator.
- On your mobile device, enable Bluetooth and search for available devices.
- Select "AV-628BT" from the list of devices to pair.
- Once paired, you can stream audio from your device to the amplifier.
USB/SD Card Playback
- Insert a USB drive into the "USB Interface" or an SD/MMC card into the "SD/MMC CARD" slot on the front panel.
- Select "USB" or "SD" as the input source. The amplifier will automatically detect and play compatible audio files (e.g., MP3, FLAC).
- Use the "Previous song", "Pause/Play", and "Next song" buttons to control playback.
Microphone Usage (Karaoke)
- Plug your microphones into the "MIC1" or "MIC2" jacks.
- Adjust the microphone volume using the "MIC VOL" knob.
- Use "M.BASS" and "M.TREBLE" to fine-tune the microphone's tone.
- Apply "ECHO" and "REVERB" effects as desired.
- The "VOCAL" button can be used to reduce or remove vocals from certain tracks for karaoke.
FM Radio Operation
- Ensure the FM antenna is connected.
- Select "FM" as the input source.
- Use the "Previous song" and "Next song" buttons to scan for radio stations.
Maintenance
- Cleaning: Use a soft, dry cloth to clean the exterior of the amplifier. Do not use liquid cleaners or solvents.
- Ventilation: Regularly check that the ventilation openings are not blocked by dust or debris.
- Storage: If storing the unit for an extended period, disconnect it from power and store it in a cool, dry place.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No power | Power cable not connected; Power switch off; Incorrect voltage. | Check power cable connection; Ensure power switch is ON; Verify correct AC (220V) or DC (12V) power supply. |
| No sound output | Incorrect input source selected; Volume too low; Speakers not connected properly; Mute function active. | Select correct input source; Increase MUSIC VOL; Check speaker connections and polarity; Press MUTE button to deactivate. |
| Bluetooth not pairing | Bluetooth mode not selected; Device too far; Device already paired with another unit. | Ensure Bluetooth input is selected; Move device closer to amplifier; Disconnect from other devices and try again. |
| USB/SD card not playing | Incorrect input source; Incompatible file format; Corrupted media. | Select USB/SD input; Ensure files are compatible (MP3, FLAC); Try another USB/SD card. |
| Microphone not working | Microphone not plugged in; MIC VOL too low; Microphone faulty. | Ensure microphone is securely plugged in; Increase MIC VOL; Test with another microphone. |
| Poor FM reception | Antenna not connected or poorly positioned. | Connect FM antenna securely; Adjust antenna position for better signal. |
Specifications
Figure 3: Technical Specifications
| Feature | Detail |
|---|---|
| Brand | LDZS |
| Model | AV-628BT |
| Amplifier Type | HiFi Digital Stereo Amplifier |
| Channels | 2.1 |
| Input Voltage | AC 220V / DC 12V (15A) |
| Output Power (Rated) | 120W |
| Maximum Power | 600W (Peak) |
| Output Impedance | 4-16Ω |
| Bluetooth Version | 5.0 |
| Media Playback | USB, SD Card (MP3, FLAC compatible) |
| Microphone Input | Dual 6.5mm jacks with Treble, Bass, Echo, Reverb, Vocal Cancellation |
| FM Frequency Range | 87.5-108MHz |
| Frequency Response | 20Hz-20KHz |
| Harmonic Distortion | < 1KHz 0.05% 4W |
| Dimensions (L x W x H) | 35cm x 26cm x 9cm |
| Certification | CE |
Figure 4: Product Dimensions
User Tips
- Power Supply: Be mindful of the dual voltage input (12V DC and 220V AC). Ensure you are using the correct power source for your application and never connect both simultaneously.
- FM Radio: If you experience poor FM reception, try adjusting the position of the antenna or using a higher quality external antenna.
- Dimensions: The amplifier measures approximately 35cm (length) x 26cm (width) x 9cm (height), which is useful for planning placement.
Warranty and Support
This product comes with a standard manufacturer's warranty. For warranty claims, technical support, or service inquiries, please contact your retailer or the manufacturer directly. Please retain your proof of purchase for warranty purposes.
