CT14 Micro Stereo Bluetooth 4.2 Amplifier Board – User’s Guide
Overview
The CT14 is a compact, Bluetooth 4.2 stereo amplifier module with built-in 5W+5W Class F output. It’s ideal for DIY audio projects, portable speakers, and embedded systems needing wireless audio playback.
Key Features
- Bluetooth Version: 4.2 (auto reconnect, plug-and-play)
- Amplifier Output: Dual 5W channels (stereo)
- Speaker Support: 2–8 Ω, 3–10 W speakers
- Power Supply: 5V regulated (via USB or lithium battery)
- Charging Port: USB input for lithium battery charging (⚠️ current-limited, no charge management)
- Audio Output: Direct speaker drive (no external amp needed)
- Transmission Distance: ~15 meters (open space)
Pinout & Connectors
| Label | Function |
|---|---|
| VCC / USB | 5V power input (regulated only) |
| GND | Ground |
| SPK+ / SPK– | Speaker outputs (Left & Right) |
| BAT+ / BAT– | Lithium battery input (3.7V) |
| CHG | USB charging port for battery |
Do not connect speaker negatives together or use external amplifiers—this can damage the onboard chip.
Powering the Module
Recommended Options
- 5V 2A regulated adapter via USB
- 3.7V lithium battery with protection circuit
Avoid
- Dry cells, power banks, or unstable multi-voltage adapters
- Batteries without protection boards (risk of overcharge/fire)
Speaker Connection
- Use 4Ω–8Ω speakers, rated 3W–10W
- Connect each speaker directly to its designated output
- Do not short speaker grounds or combine outputs
Bluetooth Usage
- Module auto-pairs with previously connected devices
- Appears as a generic Bluetooth audio device (no password)
- Supports most phones, tablets, and PCs with Bluetooth 4.0+
LED Indicator Behavior
- Flashing: Waiting for connection
- Solid: Connected and playing
Battery Charging Notes
- USB port supports current-limited charging
- No onboard charging management (no cutoff or balancing)
- Use only protected lithium cells from reputable sources
For safety, never leave charging unattended. Damage from improper use is not covered by manufacturers.
Integration Tips
- Keep module away from metal enclosures to preserve Bluetooth range
- Mount on non-conductive standoffs to avoid shorts
- For embedded builds, consider adding:
- Voltage regulator for stable 5V input
- Passive low-pass filter for cleaner audio
- Heat dissipation if driving high-power speakers
Application Ideas
- DIY Bluetooth speaker
- Embedded audio feedback system
- Portable audio playback for medical or industrial devices
- Wireless sound module for robotics or kiosks
Troubleshooting
| Issue | Solution |
|---|---|
| No sound output | Check speaker polarity and power supply |
| Bluetooth not connecting | Reset paired devices, ensure 5V stable input |
| Distorted audio | Use regulated 5V 2A supply, check speaker load |
| Overheating | Reduce speaker wattage or add heat sinking |