S.M.S.L H400

Safety Notes

• Install this unit in a well-ventilated, cool, dry, clean place, away from direct sunlight, heat sources, vibration, dust, moisture, or cold.
• Use only the voltage specified for this unit. Using a higher voltage is dangerous and may cause fire, damage to the unit, or personal injury. The company will not be held responsible for any damage resulting from the use of this unit with a voltage other than that specified.
• Do not attempt to modify or fix this unit yourself. Contact a salesperson or customer service when any service is needed. The cabinet should never be opened for any reason.
• When not planning to use this unit for long periods of time (e.g., when going on vacation), disconnect the power cable from the AC wall outlet.

Important Note: The product specifications and information mentioned in this manual are for reference only. The content of this manual is subject to change without notice.

Warranty Terms

1. Term of Service: Foshan Shuangmusanlin Technology Co., Ltd. promises to offer good-quality products. If the product is broken within 7 days after purchasing under normal use, you can choose to send it back for return, replacement, or repair (only the product that does not affect second sales can be returned). Repairing for free is provided for one year if you use it normally.

2. Proof of Purchase: The date of purchase is in accordance with the date on the invoice or receipt used by the seller. If you buy it online, you can show a screenshot of the trade.

3. Warranty Void Conditions: If inappropriate usage causes the unit to be damaged, the warranty will be void. This includes:

• All damages by inappropriate use, including using it under non-normal working environment or without following the instructions.
• Dismantling, refitting, or repairing by the user in private.
• Causing damage by using fittings other than the designated or accredited ones.
• Inability to provide credible proof of purchase.

4. Repair Process: Send the unit back to the company for repairing.

5. Contact: Contact your S.M.S.L Audio reseller for a return or replacement.

Features

• Fully balanced discrete design for ultra-high power output.
• Low distortion (0.00006% THD+N) and high SNR (133dB).
• High output power: 15W at 16 ohms, 7.5W at 32 ohms.
• Relay Switching Volume attenuator, completely avoids imbalance between the left and right channels.
• 3 gears gain control, with low gain specially optimized for IEMs.
• Pre-out function, can be used as a Hi-End pre-amplifier.
• Tempered glass optically bonded IPS display screen.
• Ultra-compact design, very suitable for desktop systems.
• High precision low-temperature drift resistance, performance is not affected by temperature.
• High-quality relay and non-impact sound design.
• 20Hz to 100KHz (-0.5dB) frequency response.
• The headphone amplifier has comprehensive protections such as DC, overvoltage, and overload protection.
• Built-in high efficiency and low noise power supply system.
• Equipped with a full-function remote control.

Specifications

Note: S.M.S.L reserves the right to make improvements which may result in specification or feature changes without notice.

Parts Introduction

The unit features various input, output, and control ports. Refer to the diagrams for physical layout.

Front Panel:

• 1. 4.4mm headphone jack: For connecting 4.4mm balanced headphones.
• 2. 6.35mm headphone jack: For connecting 6.35mm headphones.
• 3. Balanced headphone jack: Another option for balanced headphone connections.
• 4. Knob [Control Knob]: Used for volume control and navigation.
• 5. Remote window [Infrared Receiver]: Receives signals from the remote control.
• 6. Indicator light [Status Indicator]: Shows the unit's operational status.
• 7. Display [Screen Display]: Shows current settings and information.

Back Panel:

• 8. XLR balanced input: For balanced audio source input.
• 9. XLR Pre-output: Balanced output for connecting to other audio equipment.
• 10. Grounding pillar [Grounding Terminal]: For grounding the unit to reduce noise.
• 11. RCA input: For unbalanced audio source input.
• 12. RCA Pre-output: Unbalanced output for connecting to other audio equipment.
• 13. USB upgrade port [USB Port for Firmware Updates]: For updating the unit's firmware.
• 14. Grounding control switch [Grounding Control Switch]: Allows selection of grounding mode.
• 15. AC IN (100V-240VAC) [AC Power Input]: Connect the power cable here.

Indicator Status Instruction:

• Red light: Indicates standby mode.
• Red flashing light: Indicates system protection mode has been triggered.

When protection is triggered, turn off the power promptly. Try unplugging all connected load equipment to keep the power on in a no-load state. If the unit still cannot be used normally, please contact the staff for inspection and processing.

Function Introduction

INPUTS SOURCE (Input Method)

• XLR INPUT: Accepts balanced audio signals via XLR connectors.
• RCA INPUT: Accepts unbalanced audio signals via RCA connectors.

OUTPUTS SOURCE (Output Method)

• PRE OUT: Provides pre-amplified audio output (balanced and unbalanced).
• HEADPHONE: Outputs audio directly to headphones.

VOLUME MODE (Volume Adjustment)

• REAL TIME: When the volume knob is turned quickly, the relay adjusts the volume step-by-step to the set level.
• SOFT: Volume relays change at intervals to avoid over-frequent relay operation and to prolong relay life.

GAIN MODE (Gain Setting)

• LOW GAIN: Lower amplification level, optimized for sensitive IEMs.
• MID GAIN: Medium amplification level.
• HIGH GAIN: Higher amplification level for less sensitive headphones.

DIMMER SETTING (Automatic Screen Off)

The screen can be set to automatically turn off within a range of 5 to 60 seconds. After setting, the screen will go off within the specified time. Operating the remote control or the knob will re-light the screen. This feature helps reduce light pollution and enhances the comfort of the listening environment.

BRIGHTNESS (Display Brightness Setting)

Adjustable brightness level from 1% to 99%.

INFORMATION & RESET

Long-press the middle button of the knob to clear all settings and reset the unit to its default configuration.

Remote Control

About the Remote Control

• If the remote control is still ineffective when it is close to the machine, replace it with a new battery.
• If the user does not use the remote control for a long time, remove the battery from the remote control.
• Dispose of used batteries in accordance with local regulations on battery disposal.

Operating the Remote Control

The remote control has the following functions:

• [Power Symbol] Power ON/OFF: Turns the unit on or off.
• [Up Arrow] Up: Navigates menus upwards.
• [Menu/OK Button] MENU/OK: Enters menus or confirms selections.
• [Right Arrow] Right: Navigates menus to the right.
• [Left Arrow] Left: Navigates menus to the left.
• [Down Arrow] Down: Navigates menus downwards.
• [Input Select Button] Input select: Switches between input sources.
• [Mute Button] Mute: Mutes the audio output.
• [FN Button] FN button (switching earphone/preamp outputs): Toggles between headphone and pre-amplifier outputs.
• [Volume Up Button] Volume +: Increases the volume.
• [Volume Down Button] Volume -: Decreases the volume.

Note: This remote controller uses 2 x R03/AAA batteries.