AK4493 Bluetooth Audio Receiver and USB DAC User Manual

1. Introduction

This manual provides detailed instructions for the installation, operation, and maintenance of your Dual parallel AK4493 Bluetooth 5.4 QCC5181 lossless receiving USB flash drive APP lossless music module. This high-performance audio device combines a Bluetooth audio receiver with a USB DAC, offering versatile connectivity and superior sound quality.

2. Key Features

• Dual Parallel AK4493SEQ: Utilizes two AK4493SEQ DAC chips for enhanced audio performance.
• Advanced Bluetooth Connectivity:
  • Supports Qualcomm QCC5125 (Bluetooth version 5.1) and QCC5181 (Bluetooth version 5.4).
  • Comprehensive codec support: LDAC, AAC, aptX, aptX LL, aptX HD, aptX Adaptive.
  • Supports 24BIT96K audio via LDAC (requires mobile phone support).
• USB Playback:
  • Supports WAV, FLAC, APE, and MP3 audio formats.
  • Up to 24BIT48K sampling rate for USB playback.
• Flexible Power Supply Design:
  • Compatible with DC-DC5V and linear power supply (7805 design).
  • Optional internal boost and external power jumper caps for flexible voltage selection.
  • Single input socket for both DC and AC power.
  • All internal power supplies utilize TI low-noise LDOs for clean power delivery.
• Operational Amplifier Support:
  • Supports four dual operational amplifiers.
  • Features IV operational amplifier patch 072 and LPF operational amplifier JRC5532DD (default).
  • The LPF operational amplifier is replaceable with other dual operational amplifiers.
• Sound Card Functionality: Includes a sound card socket (PCM24BTI96K).
• APP Control: Supports control via a dedicated APP when connected via USB drive.

3. Specifications

4. Setup Instructions

Carefully follow these steps to set up your AK4493 Bluetooth Audio Receiver and USB DAC module.

4.1 Component Overview

4.2 Wiring Diagram and Connections

Refer to the following diagram for proper connection of power, audio input/output, and Bluetooth antenna. The diagram includes Chinese labels, which are interpreted below:

1. Power Input:
   • The board supports both DC-DC5V and linear power supplies.
   • Connect your power source to the designated AC~/DC+ and GND terminals (labeled as 'AC~/DC+' and 'GND' near the bottom right of the diagram). The board is designed to share a single input socket for both AC and DC.
   • Use the jumper caps (e.g., '内部DCDC, +5V 跳帽' - Internal DCDC, +5V Jumper) to select between internal boost or external power options, and to configure for positive and negative voltage designs (e.g., '内部-12V, 外部-12V' - Internal -12V, External -12V; '内部+12V, 外部+12V' - Internal +12V, External +12V) as needed.
2. USB Input:
   • Connect a USB cable to the GND, DM, D+, +5V terminals (labeled at the top left of the diagram) for USB playback or APP control.
3. Bluetooth Antenna:
   • Attach the Bluetooth antenna to the 'BT 天线' (BT antenna) connector at the top right of the diagram for optimal wireless performance.
4. Audio Input (Analog):
   • For analog input, connect your source to the LIN (Left Input), GND, and RIN (Right Input) terminals (labeled '输入' - Input, at the bottom left).
5. Audio Output (Analog):
   • Connect your amplifier or active speakers to the LOUT (Left Output), GND, and ROUT (Right Output) terminals (labeled '输出' - Output, at the bottom middle).
6. Operational Amplifier Power:
   • The board provides connections for L-, GND, L+, R-, GND, R+ for +12V and -12V power to the operational amplifiers (labeled on the left side, '+12V, -12V').
7. Infrared Receiver:
   • Connect an infrared receiver to the IR, GND, and +3V3 terminals (labeled on the left side) if remote control functionality is desired.
8. Sound Card Socket:
   • Utilize the PCM24BTI96K sound card socket for sound card functionality.

Important: Ensure all connections are secure and correctly polarized before applying power to prevent damage to the module or connected equipment.

5. Operation

5.1 Bluetooth Audio Playback

1. Ensure the Bluetooth antenna is connected.
2. Power on the module. The Bluetooth LED (BTLED+) should indicate its status (e.g., blinking for pairing mode, solid for connected).
3. On your source device (smartphone, tablet, computer), enable Bluetooth and search for available devices.
4. Select the AK4493 module from the list of devices to pair.
5. Once paired, audio from your source device will be streamed to the AK4493 module.
6. For optimal sound quality, ensure your source device supports high-resolution Bluetooth codecs like LDAC, aptX HD, or aptX Adaptive. LDAC playback at 24BIT96K requires compatible mobile device support.

5.2 USB Playback and APP Control

1. Connect the module to a computer or compatible USB host device using the USB input terminals.
2. The module can function as a USB DAC, allowing playback of WAV, FLAC, APE, and MP3 files up to 24BIT48K sampling rate.
3. If supported, install the dedicated APP on your computer or mobile device. This APP allows for control and management of the module's functions via the USB connection.

5.3 Operational Amplifier Replacement (LPF)

The Low-Pass Filter (LPF) stage uses a JRC5532DD dual operational amplifier by default (labeled 'LPF 运放 5532DD' on the diagram). This component is socketed, allowing for replacement with other compatible dual operational amplifiers to customize the sound signature. Exercise caution and ensure proper orientation when replacing op-amps.

6. Maintenance

• Cleaning: Use a soft, dry cloth to clean the module. Avoid using liquid cleaners or solvents.
• Environment: Keep the module in a dry environment, away from direct sunlight, high temperatures, and humidity.
• Handling: Handle the board with care to avoid damaging components. Avoid touching the circuit board directly with bare hands to prevent static discharge.
• Power Off: Always disconnect power before making any changes to wiring or components.

7. Troubleshooting

• No Power:
  • Check all power connections and ensure the power supply is providing the correct voltage (DC-DC5V or appropriate linear supply).
  • Verify jumper cap settings for power configuration.
• No Bluetooth Connection:
  • Ensure the Bluetooth antenna is securely connected.
  • Make sure the module is in pairing mode (check BTLED+ indicator).
  • Confirm Bluetooth is enabled on your source device and it's within range.
  • Try restarting both the module and your source device.
• No Audio Output:
  • Check all audio input and output connections (LIN/RIN, LOUT/ROUT).
  • Verify that the source device is playing audio and its volume is turned up.
  • Ensure your amplifier or active speakers are powered on and correctly configured.
  • If using USB playback, confirm the module is recognized as an audio device by your computer.
• Poor Audio Quality:
  • Ensure high-quality audio files are being used.
  • For Bluetooth, check if your source device supports and is using high-resolution codecs (LDAC, aptX HD).
  • Verify that the power supply is stable and free from noise.
  • If you have replaced op-amps, ensure they are correctly installed and compatible.

8. User Tips

• Op-Amp Rolling: Experiment with different compatible dual operational amplifiers in the LPF stage to fine-tune the audio characteristics to your preference.
• Power Supply Optimization: For the best audio performance, consider using a high-quality, low-noise linear power supply if your setup allows for it, leveraging the module's flexible power input options.
• Antenna Placement: Position the Bluetooth antenna away from other electronic components and metal objects to maximize signal strength and range.

9. Warranty and Support

For any issues, technical support, or warranty claims, please contact the seller or manufacturer directly. Keep your purchase records handy for faster service.