Aune S18 EVO DAC Instruction Manual

1. Product Overview

The Aune S18 EVO is a high-performance Digital-to-Analog Converter (DAC) designed for Hi-Fi audio systems, PCs, and home audio setups. It features advanced technologies such as a 10MHz clock input, 32bit/768kHz/DSD512/MQA support, dual AKM AK4497 DAC chips, and 3rd-generation PLL/Clock Sync technology for precise audio reproduction.

Figure 1: Aune S18 EVO DAC front and rear panel overview. This image illustrates the various controls and connection ports on the device, including volume controls, input selection buttons, display, XLR/RCA outputs, and digital inputs.

2. Important Safety Information

Voltage Requirement: The Aune S18 EVO DAC must be used with a 110V power supply. Connecting the device to an excessive voltage will cause damage and void the warranty. Always verify your power source voltage before connecting the device.

Ventilation: Ensure adequate ventilation around the unit to prevent overheating. Do not block ventilation openings.

Moisture: Keep the device away from water or excessive moisture. Do not operate with wet hands.

Cleaning: Disconnect power before cleaning. Use a soft, dry cloth. Do not use liquid or aerosol cleaners.

3. Setup and Connections

3.1 Front Panel Controls

• Volume Up/Down: Adjusts the output volume.
• Short Press (Left/Right Arrows): Switches input channels.
• Long Press (Left/Right Arrows): Mutes/restores memorized volume output.
• Short Press (V/S button): Switches filter mode.
• Long Press (V/S button): Activates standby/wake mode.
• Display: Shows current input, volume, and other status information.

3.2 Rear Panel Connections

• XLR (R/L) Output: Balanced analog audio output.
• RCA Output: Unbalanced analog audio output.
• AES Input: Digital audio input (AES/EBU).
• Optical Input: Digital audio input (TOSLINK).
• Coaxial Input: Digital audio input (S/PDIF).
• USB Input: Connects to a computer or other USB audio source.
• External Clock Input (10MHz): For connecting an external 10MHz clock source for enhanced synchronization.
• Bluetooth Antenna Interface: For connecting the included Bluetooth antenna.
• Power Switch: Turns the unit on or off.
• Power Interface: Connects to the 110V AC power adapter.

3.3 Connecting Audio Sources

Connect your digital audio sources (PC via USB, CD player via Coaxial/Optical, etc.) to the corresponding input ports on the rear panel. For Bluetooth, attach the antenna and pair your device as described in Section 4.4.

3.4 Connecting to Amplifiers/Speakers

Connect the S18 EVO's RCA or XLR outputs to your amplifier or active speakers. Use XLR connections for optimal performance if your amplifier supports them.

4. Operation

4.1 Powering On/Off

Flip the power switch on the rear panel to the 'ON' position to power on the device. To turn off, flip the switch to 'OFF'. For temporary standby, long-press the V/S button on the front panel.

4.2 Input Selection

Short-press the left or right arrow buttons on the front panel to cycle through available input channels (USB, Coaxial, Optical, AES, Bluetooth, etc.). The selected input will be shown on the display.

4.3 Volume Control

Use the 'Volume Up' and 'Volume Down' buttons on the front panel to adjust the output volume. The current volume level is indicated on the display.

4.4 Filter Modes

The S18 EVO features custom DAC chip filters. Short-press the V/S button to cycle through different filter modes, optimizing the sound characteristics for your preference. Refer to the display for the active filter mode.

4.5 Bluetooth Pairing

To pair a Bluetooth device, select the Bluetooth input. The S18 EVO will enter pairing mode. On your mobile device or computer, search for available Bluetooth devices and select 'Aune S18 EVO'. Once connected, audio will stream wirelessly to the DAC.

5. Key Technologies

5.1 3rd-Gen Fully Synchronized PLL Technology

The S18 EVO integrates a 3rd-generation Phase-Locked Loop (PLL) core with full-clock synchronization. This technology dynamically tracks and eliminates errors between the reference and feedback clocks, significantly reducing clock signal jitter to the femtosecond level. This ensures a highly unified time reference across all units during high-speed data processing, providing a stable, pure, and synchronized clock foundation for the entire system.

Figure 2: Illustration of the 3rd-Gen PLL Core, a key component for precise clock synchronization.

5.2 XMOS Optimization for USB Audio

Unlike conventional USB DAC designs, the S18 EVO employs an ultra-low-jitter PLL to supply superior clock signals to the XMOS chip. This approach, combined with Aune's customized drivers, ensures full-device synchronization and unlocks the true potential of XMOS for high-fidelity USB audio reproduction.

Figure 3: Close-up view of the XMOS chip, central to the S18 EVO's USB audio processing.

5.3 Full-Channel IIS Synchronized Direct-to-DAC Architecture

All digital inputs (AES, optical, and coaxial) are reconditioned through digital synchronization technology combined with a low-jitter PLL. This ensures that all signals are fed into the DAC via the IIS interface, delivering higher fidelity, more natural, and truer sound reproduction across every input channel.

Figure 4: Diagram illustrating the IIS synchronized direct-to-DAC architecture for various digital inputs.

5.4 Hi-Fi-Grade Bluetooth with PLL Clock Synchronization

Conventional Bluetooth signals often exhibit high jitter. The S18 EVO utilizes Aune's in-house Bluetooth + PLL technology to recondition the Bluetooth digital signal before it reaches the DAC. This process achieves high-fidelity audio even when streaming via Bluetooth.

5.5 Dual AK4497 DACs with Precision Synchronization

The S18 EVO employs an external PLL to provide a clock reference for its two AK4497 DAC chips. This, combined with mirrored circuitry, layout, and components, ensures highly coordinated left and right channels, recreating a cohesive soundstage.

Figure 5: A distinctive global clock synchronization architecture diagram, showing how various inputs are processed and synchronized before reaching the DACs.

6. Maintenance

• Cleaning: Use a soft, dry, lint-free cloth to clean the exterior of the unit. Avoid abrasive cleaners, solvents, or chemical sprays.
• Ventilation: Ensure the ventilation slots are clear of dust and obstructions to maintain proper airflow.
• Storage: When not in use for extended periods, store the device in a cool, dry place, away from direct sunlight and extreme temperatures.
• Handling: Handle the unit with care. Avoid dropping or subjecting it to strong impacts.

7. Troubleshooting

• No Power:
  • Ensure the power cable is securely connected to both the S18 EVO and a working 110V power outlet.
  • Check the power switch on the rear panel is in the 'ON' position.
  • Verify the power outlet is functional.
• No Sound Output:
  • Confirm the correct input source is selected on the S18 EVO.
  • Check all audio cables (RCA, XLR) are securely connected between the S18 EVO and your amplifier/speakers.
  • Ensure the volume level on the S18 EVO is not muted or set too low.
  • Verify your amplifier/speakers are powered on and set to the correct input.
  • If using USB, ensure the correct audio output device is selected in your computer's sound settings and Aune's customized drivers are installed.
• Bluetooth Connection Issues:
  • Ensure the Bluetooth antenna is securely attached.
  • Verify the S18 EVO is in Bluetooth input mode and pairing mode is active.
  • Disable and re-enable Bluetooth on your source device.
  • Move your source device closer to the S18 EVO to reduce interference.
• Distorted Sound:
  • Check for loose cable connections.
  • Ensure the source audio file is not corrupted or of low quality.
  • Verify the sample rate and bit depth settings on your source device match the S18 EVO's capabilities.
  • Try a different input source to isolate the problem.

8. Specifications

9. Warranty Information

The Aune S18 EVO DAC comes with a 2-year warranty from the date of purchase. This warranty covers manufacturing defects and malfunctions under normal use. It does not cover damage caused by misuse, accident, unauthorized modification, or connection to incorrect voltage (e.g., exceeding 110V). Please retain your proof of purchase for warranty claims.

10. Customer Support

For technical assistance, warranty claims, or any questions regarding your Aune S18 EVO DAC, please contact Aune customer support through their official website or the retailer from whom you purchased the product. Please have your model number (S18 EVO) and proof of purchase ready when contacting support.