CT14 Micro 4.2 Stereo Bluetooth Amplifier Board 5W+5W Audio Module with Charging

Specifications

• Bluetooth Version: 4.2 (Backwards compatible)
• Transmission Range: Up to 15 meters (Open space)
• Output Power: 5W + 5W (Stereo)
• Supported Speakers: 2Ω to 8Ω (4Ω 5W recommended for best performance)
• Supply Voltage: 3.7V Lithium Battery or 5V DC (Micro USB)
• Charging Interface: Micro USB (5V Input) - Supports charging while playing (Note: Requires sufficient current)
• Audio Format Support: WAV, APE, FLAC, MP3 (Lossless decoding)
• Dimensions: 40mm x 20mm x 12mm
• SNR (Signal to Noise Ratio): 90dB
• THD+N: -70dB
• Crosstalk: -86dB

Applications

• DIY Bluetooth Speakers: Convert old wired speakers into modern wireless units.
• Portable Audio Projects: Perfect for 3D printed boomboxes or custom wooden enclosures.
• Vehicle Audio: Add Bluetooth capability to older car stereo systems (requires 5V buck converter).
• Smart Home Alerts: Use as a wireless notification speaker for IoT systems.
• Toy Modification: Upgrade kids' toys with custom sounds and wireless control.

Project Evolution

• The Journey: If you have mastered basic buzzers and mono amplifiers (like the LM386), you are ready for high-fidelity stereo sound.
• The Upgrade: This module moves you away from "beep-boop" electronics to consumer-grade audio. It unlocks the ability to stream high-quality music directly from your phone, teaching you about power management and audio signal integrity.
• Effort Level: Intermediate. Requires basic soldering skills to attach wires to the pads.
• Minimum Hardware: You will need a 3.7V Li-ion battery (like an 18650), two speakers (4Ω 5W), and connecting wires.

Wiring Guide

• L- / L+: Left Speaker Negative / Positive.
• R- / R+: Right Speaker Negative / Positive.
• BAT- / BAT+: 3.7V Lithium Battery connection (Essential for portability).
• Micro USB: Charging Input (5V). Warning: Do not use this as the primary power source for high-volume playback without a battery connected, as voltage drops may cause restarts.
• Warning: The charging interface allows you to charge the connected lithium battery. Ensure your battery has its own PCM (Protection Circuit Module) if you plan to leave it charging unattended.

Package Includes:

• 1 x CT14 Micro 4.2 Stereo Bluetooth Amplifier Board (5W+5W)
• 3 x Plug-in Connector Wires (2-Pin JST-PH 2.0mm cables for Battery & Speakers)

Frequently Asked Questions (FAQ)

• Can I power this directly from a 5V USB charger without a battery?
  It is possible but not recommended. At high volumes, the current draw spikes, which may reset the module if the USB supply isn't strong enough. A battery acts as a buffer.
• What is the Bluetooth device name?
  The device typically appears as "DW-CT14+" or "CT14" in your Bluetooth list.
• Does it support stereo sound?
  Yes, it has distinct Left and Right channel outputs (5W each).
• Can I use 8-ohm speakers?
  Yes, but the volume will be slightly lower compared to 4-ohm speakers.
• How do I charge the battery?
  Simply plug a standard Micro-USB cable into the onboard port. The module handles the charging current for the 3.7V battery.
• Why is there a humming noise in my audio?
  This is usually a "ground loop" issue or poor power supply filtering. Keep speaker wires short and twisted. Ensure your battery connections are solid.
• Can I connect this to my car's 12V battery?
  No! Connecting 12V will instantly destroy the board. You must use a Buck Converter to step down 12V to 5V.
• Does it have a microphone for calls?
  No, this module is strictly for audio playback/streaming.
• Can I modify the Bluetooth name?
  No, the name is hardcoded into the main chip and cannot be changed without specialized programmer tools.
• What happens if I reverse the battery polarity?
  The board does not have reverse polarity protection. Reversing +/- will damage the IC. Probots Logic-Safe advice Always double-check polarity before soldering!
• Can I use two of these boards at once?
  You can physically use two, but your phone will likely only connect to one at a time unless your phone supports "Dual Audio" features.
• Is a heatsink required?
  For normal use with 5W speakers, no. If using at max volume continuously in a hot enclosure, a small stick-on heatsink on the main chip helps.
• What is the maximum range?
  Reliably 15 meters in line-of-sight. Walls and metal enclosures will reduce this.
• Can I add a physical volume knob?
  Not directly to the board. Volume is controlled via the connected Bluetooth device (phone/laptop).
• Does it support APTX or LDAC?
  No, it supports standard SBC/AAC decoding which is sufficient for general music listening.
• How do I know if it is paired?
  There is an onboard LED status indicator. It blinks when waiting for connection and stays solid when connected.
• Can I use a 9V battery?
  No. 9V batteries cannot supply the required current and the voltage is too high. Use 3.7V Li-ion (18650).
• Does it turn off automatically?
  It enters a standby mode when disconnected, but we recommend adding a physical On/Off switch between the battery and the board.
• Is the USB port for data transfer? No, the Micro USB port is strictly for power input/charging.
• What gauge wire should I use for speakers?
  Standard 22-24 AWG wire is perfect for these short runs and power levels.