1. Introduction
The WONDOM BDM8-A is a high-performance stereo audio amplifier board designed for enthusiasts seeking powerful and clear sound. Boasting a 2x300W power output, this Class D amplifier utilizes the TPA3255 chip from Texas Instruments, ensuring high efficiency and robust performance for various audio applications, including home theater systems.
This manual provides detailed instructions for the safe and proper setup, operation, and maintenance of your BDM8-A amplifier board.
Product Overview Video
This video provides a visual introduction to the BDM8-A amplifier board, highlighting its features and ports.
Key Features
- High Power Output: 2x300W (4Ω) for strong driving capacity.
- TI TPA3255 Amp IC: High reliability and performance.
- High Efficiency: Over 90% work efficiency.
- Low Power Consumption: Idle power of 3.3W (signal detected @ 36V).
- Wide Supply Voltage: DC 18V - 48V.
- Optimal Thermal Performance: Equipped with a robust heatsink and fan cooling for effective heat dissipation.
- High Quality Components: Utilizes LH.NOVA main filter electrolytic capacitors, Sagami inductors from Japan, and high precision surface mount resistors.
- Bypass Mode: Simple signal transmission for pure and authentic audio.
2. Safety Guidelines
Please read and adhere to the following safety guidelines to prevent damage to the product and ensure user safety:
- Power Supply: Ensure the power supply is within the specified voltage range of DC 18V - 48V. Using an incorrect voltage or reverse polarity can damage the board and void the warranty.
- Connections: Always disconnect the power source before making or changing any connections to the amplifier board.
- Heat Dissipation: The board is equipped with a heatsink and fan. Ensure proper ventilation around the board to allow for effective heat dissipation. Do not obstruct the fan or heatsink.
- Operating Environment: The rated operating temperature range is 0-40°C. Avoid using the product in industrial or special industrial environments unless specifically designed for such conditions.
- No Hot Plugging: Do not hot plug or change settings while the board is powered on.
- DIY Product: This product is intended for DIY use. Visible damage or use on screw holes or tinning of solder pads may invalidate the warranty.
3. Product Components and Layout
The BDM8-A amplifier board features a compact design with essential components for high-fidelity audio amplification.
Board Layout
Key Components
- TPA3255 Chip: The core of the amplifier, providing high-performance Class D amplification.
- Heatsink and Fan: Integrated for optimal thermal management and preventing overheating.
- LH.NOVA Main Filter Electrolytic Capacitors: Ensure strong and stable power supply.
- Sagami Inductors (from Japan): Contribute to clear and powerful sound output.
- High Precision Surface Mount Resistors: Ensure a good signal-to-noise ratio for the entire machine.
4. Setup and Connections
Follow these steps to correctly set up your BDM8-A amplifier board.
Port Introduction
- Line Input: This is where the audio source is connected to the amplifier. It uses a Connector Header Through Hole with 5 pins for a reliable audio input connection.
- Power Input: This is where the DC power source (18V - 48V) should be connected. It uses a 2-Circuit Barrier Block Connector with screws for a secure and stable power supply connection.
- Speaker Output: Designed for connecting speakers to the amplifier. It utilizes a 2-Position Wire-to-Board Terminal Block Horizontal.
Connection Setup
- Speaker Output Port Connection:
- Connect the positive and negative terminals of your speakers to the corresponding positions on the 2-Position Wire-to-Board Terminal Block Horizontal.
- Ensure a tight and secure connection for optimal audio performance.
- Power Input Connection:
- Connect the positive and negative terminals of your DC power source (18V - 48V) to the 2-Circuit Barrier Block Connector.
- Tighten the screws to secure the power connection.
- Line Input Connection:
- Connect the audio source by using a 3.5mm cable to the Connector Header Through Hole with 5 pins.
- Ensure that each pin is correctly aligned with the corresponding channel.
Important Note:
- The BDM8-A product does not include Bluetooth functionality. If you require Bluetooth, please consider the BDM8 model.
- There is no volume control module on the BDM8-A, so the volume cannot be adjusted directly on the board. It cannot be used with a potentiometer or volume knob.
- The selection switch on the top board of the BDM8-A is only functional when using the BDM8 product (which has Bluetooth). For BDM8-A, this switch should remain in the "L" mode. If set to "BT_L", the BDM8-A board will not operate.
5. Operation
Once all connections are securely made and verified, you can power on the amplifier board.
Bypass Mode
The BDM8-A operates in a bypass mode, offering simple signal transmission:
- Simple Signal Transmission: The audio signal is directly transmitted from the source device to the amplifier through a 3.5mm audio cable. This preserves the details and features of the original audio signal to the greatest extent possible, reducing signal loss and distortion, and making the sound purer and more authentic.
- Easy to Operate: The 3.5mm direct mode provides an extremely convenient connection method. Simply connect the device to the amplifier via a 3.5mm audio cable without the need for complex settings and adjustments.
- Wide Compatibility: Almost all modern electronic devices are equipped with this interface. Therefore, the 3.5mm pass-through mode of the amplifier can be easily connected to various devices and has strong compatibility.
- Suitable for Various Scenarios: Whether enjoying music, watching movies at home, or using portable audio devices for small gatherings, outdoor picnics, etc., the 3.5mm direct mode can quickly transmit audio signals from different devices to the amplifier for amplification and playback.
6. Specifications
General Product Parameters
| Parameter | Value |
|---|---|
| Chip | TPA3255 |
| Product Model | BDM8-A |
| Power Supply Voltage | DC 18-48V |
| Audio Input | 3.5mm Signal Input |
| Output Channel | Dual Channel Stereo Sound (2.0) |
| Output Power | 300W+300W (4ohm) |
| Frequency Response | 20Hz-20KHz |
| Dynamic Range | >100dB |
| SNR | >111dB |
| Work Efficiency | >90% |
| Product Weight | 254.5g |
| Product Size | 120.2*80.1*37.5mm |
Electrical and Audio Performance
| Parameter | Conditions | Output | Min. | Typ. | Max. | Units |
|---|---|---|---|---|---|---|
| Number of Channels | 2 | |||||
| Minimum Load Impedance | 3 | 4 | Ω | |||
| Efficiency | 2x150W @ 36V, 4Ω, 1kHz | 85 | % | |||
| Nominal Power Requirement | @36V, 1kHz | 300 | W | |||
| Operating Voltage | @ 1kHz, 4Ω | 18 | 24 | 36 | V | |
| Idle Power | Signal detected @ 36V | 3.3 | W | |||
| Switching Frequency | SD Floating @ 36V | 450 | kHz | |||
| Power Consumption | 1/4 of max output power @ 4Ω, 36V, 1kHz | 90 | W | |||
| 1/8 of max output power @ 4Ω, 36V, 1kHz | 50 | W | ||||
| Number of Channels | SD short to GND | 0.1 | mW | |||
| Amp Gain | Line in | OUT1 OUT2 | 27.53 27.47 | dB | ||
| SNR | Line In 2x150W @ 4Ω, A-weighting | OUT1 OUT2 | 95.0 94.5 | dB | ||
| THD + N | Line In 1W @ 4Ω, 1kHz | OUT1 OUT2 | 0.0048 0.0050 | % | ||
| Output Noise Level | Line In A-weighting, Input Connect to GND | OUT1 OUT2 | 235 257 | uV | ||
| Input Impedance | Line In @ 4Ω, 1kHz | 20 | KΩ | |||
| Input Sensitivity | Line In, 2 x 150W @ 4Ω, 1kHz | OUT1 & OUT2 | 1 | V | ||
| DC Offset | 15 | mW |
Performance Graphs
Product Dimensions
7. Maintenance and Thermal Management
Proper maintenance ensures the longevity and optimal performance of your BDM8-A amplifier board.
Fan Cooling
The BDM8-A includes an integrated fan for enhanced heat dissipation. This fan helps maintain an ideal operating temperature, preventing overheating and maximizing the lifespan of the amplifier. If you prefer not to use the fan, it can be unplugged without affecting the core functionality of the amplifier board.
Ensure that the heatsink and fan are kept clear of dust and debris. Periodically inspect and clean them if necessary to maintain efficient cooling.
8. Troubleshooting and FAQ
Common Issues and Solutions
- No Sound Output:
- Check all power and audio input connections for secure contact.
- Verify that the power supply voltage is within the DC 18-48V range.
- Ensure the audio source is functioning correctly.
- Confirm that speakers are properly connected and functional.
- If using the selection switch (for BDM8 model), ensure it is in the correct "L" mode for BDM8-A.
- Distorted Sound:
- Check audio input cable for damage or loose connections.
- Ensure the audio source is not overdriving the input.
- Verify speaker impedance matches the amplifier's capabilities (4Ω recommended for 300W output).
- Overheating:
- Ensure the fan is operating and not obstructed.
- Provide adequate ventilation around the amplifier board.
- Verify the load impedance of the speakers is appropriate.
- "Pop" Sound on Power On/Off:
- Some amplifier designs may exhibit a slight "pop" sound during power cycling. This is often normal for high-power amplifiers without dedicated soft-start/anti-pop circuits.
- To minimize this, ensure your audio source is turned off or muted before powering the amplifier on or off.
Frequently Asked Questions
- Does the BDM8-A have Bluetooth?
No, the BDM8-A model does not include Bluetooth functionality. If Bluetooth is required, please consider the BDM8 model.
- Can the volume be controlled directly on the board?
No, the BDM8-A does not have a built-in volume control module. Volume must be controlled via the audio source device.
- Can the BDM8-A be bridged for mono output?
The BDM8-A is designed for 2.0 channel stereo output and cannot be bridged for mono operation.
9. User Tips
- External Volume Control: Since the BDM8-A lacks onboard volume control, it is highly recommended to use an audio source with adjustable output volume or an external pre-amplifier/volume control unit for convenient sound level management.
- Power Supply Quality: Using a high-quality, stable DC 18-48V power supply is crucial for achieving the best audio performance and minimizing noise.
- Speaker Matching: For optimal performance, ensure your speakers are rated for the amplifier's output power (300W per channel at 4Ω) and have an appropriate impedance.
- Wiring: Use good quality, appropriately gauged speaker wire and audio cables to prevent signal loss and ensure clear sound.
10. Warranty and Support
WONDOM products come with a one-year warranty starting from the date of purchase. Please note the following conditions:
- Warranty Invalidation: The warranty may be invalidated by visible damage, use on screw holes, tinning of solder pads, or damage caused by incorrect power sources (e.g., exceeding specified voltage range or reverse polarity).
- Repair Service: One year of free repair service is provided. The cost of shipping the product to the service center for repair is borne by the buyer. After the repair is complete, the shipping cost for returning the product to the buyer will be borne by the seller.
- Product Testing: All WONDOM products undergo thorough testing before shipment.
- Intended Use: CJL products are intended for DIY use only and do not support industrial applications.
Additional Resources
For a detailed user manual in PDF format, please refer to the official document:
For further inquiries or support, please contact WONDOM customer service.
