S.M.S.L DL300 Audio Decoder Headphone Amplifier User Manual

1. Introduction

The S.M.S.L DL300 is a high-performance audio decoder and headphone amplifier designed to deliver exceptional sound quality. It incorporates advanced AK4499EX and AK4191 chips for precise digital-to-analog conversion and features a powerful headphone amplifier circuit. This manual provides detailed instructions for the proper setup, operation, and maintenance of your DL300 unit.

2. Key Features

• AK4499EX + AK4191 Chipset: Utilizes a new stereo chip combination from AKM, offering excellent noise and THD characteristics, with complete separation of digital and analog signals for detailed sound reproduction.
• High-Power Headphone Output: Features 6.35mm and 4.4mm headphone jacks with a PLFC headphone amplifier circuit, providing two gain adjustable levels for various headphone impedances.
• Advanced PCM Filters and Tones: Offers 6 types of PCM filters and 4 tone options to customize the audio output according to user preference.
• High-Resolution Audio Support: Supports PCM playback up to 32bit/768kHz and hard decoding of DSD512.
• XMOS XU-316 Processor: Equipped with the third-generation XMOS XU-316 for robust USB audio processing.
• Extensive Input/Output: USB, Optical, Coaxial, and I²S inputs support DSD transmission. Coaxial and Optical inputs also support DOP64.
• Bluetooth Connectivity: Integrates the QCC5125 Bluetooth chip with an external antenna, supporting LDAC and apt-X HD for high-quality wireless audio streaming.

Figure 2.1: Internal AK4499EX and AK4191 Chipset for Digital/Analog Signal Separation.

Figure 2.2: Overview of DL300's core technologies and supported audio formats.

3. Package Contents

Please check that all items are present in the package:

• S.M.S.L DL300 Main Unit
• Power Cable (with various plug adapters)
• USB Cable (Type-C)
• Remote Control
• Bluetooth Antenna
• User Manual

Figure 3.1: Included accessories with the S.M.S.L DL300.

4. Controls and Interfaces

4.1 Front Panel

Figure 4.1: Front Panel Overview.

• Display Screen: Shows current input, sample rate, volume, and menu options.
• 6.35mm Headphone Jack: Standard single-ended headphone output.
• 4.4mm Headphone Jack: Balanced headphone output.
• Multi-function Knob: Controls power, volume, input selection, and menu navigation.

4.2 Rear Panel

Figure 4.2: Rear Panel Connections.

• XLR Balanced Outputs (L/R): For connecting to balanced amplifiers or active speakers.
• RCA Unbalanced Outputs (L/R): For connecting to unbalanced amplifiers or active speakers.
• Coaxial Input: Digital audio input.
• Optical Input: Digital audio input.
• I²S Input (HDMI): High-performance digital audio input.
• USB Input: For connecting to a computer or other USB audio source.
• Bluetooth Antenna Connector: For attaching the included Bluetooth antenna.
• AC Power Input: For connecting the power cable.

4.3 Remote Control

Figure 4.3: Remote Control Functions.

• ON/OFF: Power on or off the unit.
• Return: Go back to the previous menu.
• Select Up/Down: Navigate menu options.
• Enter/Exit Menu: Access or exit the main menu.
• Enter Secondary Menu: Access sub-menus.
• Switch Input: Cycle through available input sources.
• Mute: Mute or unmute audio output.
• FN Key: Customizable function key.
• Volume Increase/Decrease: Adjust the output volume.

5. Setup

1. Connect Power: Connect the provided power cable to the AC power input on the rear panel and then to a suitable power outlet.
2. Attach Bluetooth Antenna: Screw the Bluetooth antenna onto its connector on the rear panel.
3. Connect Audio Source: Choose your desired audio input (USB, Optical, Coaxial, I²S) and connect your source device to the corresponding input on the DL300 rear panel. For USB connection, use the provided USB Type-C cable.
4. Connect Output Device:
   • For headphones, plug your headphones into either the 6.35mm or 4.4mm jack on the front panel.
   • For external amplifiers or active speakers, connect the DL300's XLR or RCA outputs to your receiving equipment.
5. Power On: Press the power button on the remote control or the multi-function knob on the front panel to turn on the DL300.

6. Operating Instructions

6.1 Basic Operation

• Volume Control: Rotate the multi-function knob on the front panel or use the Volume +/- buttons on the remote control to adjust the output volume.
• Input Selection: Press the multi-function knob or the 'Switch Input' button on the remote to cycle through available input sources (USB, Optical, Coaxial, I²S, Bluetooth).
• Mute: Press the 'Mute' button on the remote control to temporarily silence the audio output.

6.2 Menu Navigation

Press the multi-function knob or the 'Enter/Exit Menu' button on the remote to access the main menu. Use the Up/Down buttons to navigate and the 'Enter' button to select options. The 'Return' button exits the current menu level.

6.3 PCM Filters and Tones

The DL300 offers various PCM filters and tone settings to fine-tune the sound. These can be accessed through the menu. Experiment with different settings to find your preferred audio characteristics.

Figure 6.1: PCM Filter Characteristics.

6.4 Bluetooth Pairing

1. Select Bluetooth as the input source on the DL300. The display will show 'BT' and indicate pairing mode.
2. On your mobile device or computer, enable Bluetooth and search for available devices.
3. Select 'S.M.S.L DL300' from the list of devices to pair.
4. Once paired, the DL300 display will confirm the connection, and you can stream audio wirelessly.

Figure 6.2: Bluetooth Connectivity Features.

6.5 Headphone Output Gain

The headphone output has adjustable gain settings. This can be configured in the system menu to match the impedance and sensitivity of your headphones, ensuring optimal performance and preventing distortion.

Figure 6.3: Headphone Output Details.

7. Maintenance

• Cleaning: Use a soft, dry cloth to clean the exterior of the unit. Avoid using abrasive cleaners or solvents.
• Ventilation: Ensure the unit has adequate ventilation. Do not block the ventilation holes.
• Environment: Keep the unit away from direct sunlight, heat sources, excessive dust, moisture, and strong electromagnetic fields.
• Power Off: Always power off the unit before disconnecting cables or moving it.

8. Troubleshooting

9. Specifications

Figure 9.1: THD+N Performance Data.

Figure 9.2: Signal to Noise Ratio Performance Data.

Figure 9.3: Dynamic Range Performance Data.

10. Warranty and Support

S.M.S.L products are typically covered by a manufacturer's warranty. For specific warranty terms, duration, and conditions, please refer to the warranty card included with your product or contact your retailer. For technical support, product inquiries, or service requests, please contact the official S.M.S.L support channels or your authorized dealer.

11. Product Video Overview