1. Introduction
The ZK-502L is a mini 2x50W Bluetooth 5.0 digital power amplifier board designed for various audio applications, particularly suitable for DIY speaker projects. It features a convenient volume control potentiometer with an integrated switch, a robust copper DC power connector, and stereo output capabilities. This manual provides detailed instructions for setup, operation, and troubleshooting to ensure optimal performance and longevity of your amplifier board.
2. Product Features
- Integrated potentiometer for volume adjustment with power switch.
- Durable copper DC power connector for stable current and heat dissipation.
- Left and right dual-channel stereo output.
- Compact and mini size for versatile integration.
- Easy to use and set up.
3. Setup Instructions
3.1. Power Supply Connection
The amplifier board requires a DC power input of 5-24V. Use a DC5.5*2.1mm connector. Ensure the power supply voltage and current are sufficient for the desired output power. Higher voltage generally leads to higher output power. For optimal performance, especially with high power output, a power supply of 18V, 19V, or 24V with a current of more than 3A is recommended.
3.2. Speaker Connection
Connect your speakers to the left and right channel output terminals (L+ L- and R+ R-). The board is compatible with speakers ranging from 30W to 200W, with impedances of 4Ω or 8Ω. Commonly used speakers are generally 8 ohms. 4 ohm speakers can also be used. If your speaker power is low (e.g., 10W-30W), use a lower power supply voltage (below 15V) to prevent speaker damage.
3.3. Bluetooth Connection
- Power on the amplifier board and ensure speakers are connected.
- Turn the audio knob to activate the indicator light.
- On your mobile phone, navigate to Bluetooth settings.
- Search for "BT-WUZHI" in the list of available devices.
- Click to connect. A "ding-dong" prompt will sound upon successful connection.
- Once connected, you can play music. The amplifier will automatically reconnect to your phone the next time it is powered on.
4. Operating Instructions
4.1. Power On/Off and Volume Control
The integrated volume knob also functions as the power switch. Rotate the knob clockwise to turn on the amplifier and increase the volume. Rotate counter-clockwise to decrease the volume and turn off the amplifier.
4.2. Audio Playback
After successfully connecting via Bluetooth, simply start playing audio from your paired device. Adjust the volume using the knob on the amplifier board or from your source device.
5. Maintenance
- Keep the amplifier board clean and free from dust. Use a soft, dry cloth for cleaning.
- Avoid exposing the board to moisture, extreme temperatures, or direct sunlight.
- Ensure proper ventilation around the board to prevent overheating, especially during prolonged use at high volumes.
- The board features self-recovery overheat protection and self-recovery short circuit protection. If these mechanisms activate, reduce power usage or strengthen heat dissipation.
6. Troubleshooting
- Q: The sound is small, but becomes muddy when louder.
- A: This indicates sound distortion. Please replace the power adapter with one that has a higher voltage level.
- Q: The sound is small, but freezes when it becomes louder.
- A: This usually means the input power supply is insufficient, or the power supply itself is intermittently powering off for protection. Replace with a higher power supply. If the power is too large, the amplifier board may overheat severely, triggering thermal protection. In this case, reduce power usage or improve heat dissipation.
7. Specifications
| Feature | Specification |
|---|---|
| Product Name | Mini Version 2x50W Bluetooth Digital Power Amplifier Board |
| Model Number | ZK-502L |
| Brand | occkic |
| Adaptive Supply Voltage | DC 5-24V (9V/12V/15V/18V/24V adapters optional; high voltage recommended for high power) |
| Compatible Speakers | 30W-200W, 4Ω, 8Ω |
| Number of Channels | 2 (Left and Right Stereo) |
| Bluetooth Version | 5.0 |
| Bluetooth Transmission Distance | 15 meters (without occlusion) |
| Protection Mechanism | Self-recovery overheat protection, self-recovery short circuit protection |
| Maximum Power Per Channel | 100 W (Total 50W x 2) |
| Package | Yes (Optional with or without shell) |
| Origin | Mainland China |
| Certification | None |
| Dimensions (L*W*H) | 55mm * 38mm * 17mm |
| Weight (without shell) | 32g |
| Housing Material Package Weight | 20g |
7.1. Power Output vs. Voltage and Speaker Impedance
The actual output power varies depending on the supply voltage and speaker impedance. The following table illustrates typical power outputs:
| Supply Voltage | Speaker Impedance | Output Power (per channel) |
|---|---|---|
| 12V | 8 ohm | 12W |
| 12V | 4 ohm | 20W |
| 15V | 8 ohm | 18W |
| 15V | 4 ohm | >30W |
| 19V | 8 ohm | 32W |
| 19V | 4 ohm | >45W |
| 24V | 8 ohm | 38W |
| 24V | 4 ohm | >50W |
8. User Tips
- Optimal Power Output: To achieve sufficient output power, ensure both the audio input signal and the power supply voltage/current are adequate. Higher supply voltage generally results in greater relative power.
- Speaker Matching: Speakers with different impedances will yield different output power. When the voltage and current are sufficient, a higher speaker impedance (ohms) will result in lower relative sound power, and vice-versa. Always match your power supply and speakers carefully.
- Heat Management: If the amplifier board heats up severely, it may trigger thermal protection. Consider reducing power usage or improving heat dissipation (e.g., adding a heatsink or ensuring good airflow) to prevent this.
9. Warranty and Support
For further technical assistance or warranty inquiries, please contact the seller, Diy Box Electronics Mall. A detailed user manual in PDF format is available for download: ZK-502L User Manual (PDF).
