eSynic ESY120uk-JP

ESYNiC Portable HiFi Headphone Amplifier User Manual

Model: ESY120uk-JP | Brand: eSynic

1. Introduction and Overview

The ESYNiC Portable HiFi Headphone Amplifier (Model ESY120uk-JP) is designed to enhance the audio experience for various devices. This compact and lightweight amplifier provides superior sound quality, noise reduction, and improved dynamics for headphones, MP3 players, smartphones, and laptops. Its robust aluminum construction and rechargeable battery make it suitable for both home and portable use.

2. Product Features

  • Compact and Portable Design: Easy to carry and use on the go.
  • 3.5mm Auxiliary Input and Output: Standard connections for wide compatibility.
  • High-Quality Stereo Output: Delivers realistic stereo sound and improved audio clarity.
  • Two-Stage Gain Switch: Allows adjustment of amplification level for optimal headphone performance.
  • Durable Aluminum Matte Surface: Reduces signal interference and ensures longevity.
  • Built-in Rechargeable Battery: Provides over 8 hours of continuous use on a single charge.
  • Wide Compatibility: Works with MP3 players, smartphones, computers, laptops, and CD players.

3. Package Contents

Please verify that all items are present in the package:

  • 1 x ESYNiC Portable HiFi Headphone Amplifier (Model ESY120uk-JP)
  • 1 x 3.5mm Audio Cable
  • 1 x USB Power Cable (Micro USB)
  • 1 x User Manual
ESYNiC Portable HiFi Headphone Amplifier package contents

Image: Contents of the ESYNiC headphone amplifier package, including the amplifier, audio cable, USB cable, and user manual.

4. Setup Instructions

  1. Connect Audio Source: Connect your audio source device (e.g., MP3 player, smartphone, laptop) to the amplifier's INPUT port using the provided 3.5mm audio cable.
  2. Connect Headphones: Connect your headphones to the amplifier's OUTPUT port.
  3. Power On: Rotate the volume knob clockwise until you hear a click and the power indicator light illuminates.
ESYNiC Headphone Amplifier connected to a smartphone and headphones

Image: The ESYNiC amplifier connected to a smartphone via the input port and headphones via the output port.

5. Operating Instructions

5.1 Power On/Off and Volume Control

To power on the amplifier, rotate the volume knob clockwise until you hear a click and the red power indicator light turns on. To power off, rotate the volume knob counter-clockwise until it clicks off. Adjust the volume to a comfortable listening level by rotating the knob.

ESYNiC Headphone Amplifier front view with ports and volume knob

Image: Front view of the amplifier showing the power/volume knob, input, and output ports.

5.2 Gain Switch Function

The amplifier features a two-stage gain switch (H/L) located on the side. This switch allows you to adjust the amplification level to match your headphones' impedance and your desired volume output.

  • 'H' (High Gain): Use this setting for higher impedance headphones (e.g., 60-150Ω) or when you require a louder output from your audio source.
  • 'L' (Low Gain): Use this setting for lower impedance headphones (e.g., 10-59Ω) or for normal listening levels to prevent distortion and conserve battery life.
ESYNiC Headphone Amplifier side view with gain switch

Image: Side view of the amplifier highlighting the 'H' and 'L' gain switch.

6. Charging the Amplifier

The ESYNiC headphone amplifier is equipped with a built-in 1000mAh lithium polymer rechargeable battery. To charge the device:

  1. Connect the provided Micro USB cable to the amplifier's DC 5V charging port.
  2. Connect the other end of the USB cable to a standard USB power source (e.g., computer USB port, USB wall adapter).
  3. The charging indicator light will illuminate during charging. Once fully charged, the light may change color or turn off, depending on the unit.

A full charge typically provides over 8 hours of continuous playback, though actual battery life may vary based on volume levels and connected headphone impedance.

ESYNiC Headphone Amplifier connected to a charger, showing battery capacity and life

Image: The amplifier connected to a power source for charging, with indicators for battery capacity and expected battery life.

7. Compatibility

The ESYNiC Portable HiFi Headphone Amplifier is designed for broad compatibility with various audio devices that feature a 3.5mm audio output. Compatible devices include:

  • MP3 Players
  • MP4 Players
  • Mobile Phones
  • Computers (Desktops and Laptops)
  • CD Players
  • Any device with a 3.5mm audio output jack

8. Maintenance

To ensure the longevity and optimal performance of your ESYNiC headphone amplifier, follow these maintenance guidelines:

  • Cleaning: Use a soft, dry cloth to clean the surface of the amplifier. Do not use liquid cleaners, solvents, or abrasive materials, as these can damage the finish or internal components.
  • Storage: Store the amplifier in a cool, dry place away from direct sunlight, extreme temperatures, and high humidity when not in use.
  • Handling: Avoid dropping the device or subjecting it to strong impacts.
  • Battery Care: For optimal battery life, avoid fully discharging the battery frequently. Charge the device regularly, even if not in constant use.

9. Troubleshooting

If you encounter issues with your amplifier, refer to the following common problems and solutions:

Problem Possible Cause Solution
No Sound
  • Amplifier not powered on.
  • Loose cable connections.
  • Audio source volume too low/muted.
  • Faulty audio cable or headphones.
  • Rotate volume knob clockwise to power on.
  • Ensure all 3.5mm cables are securely connected.
  • Increase volume on audio source and amplifier.
  • Test with a different audio cable or headphones.
Distorted Sound
  • Volume too high.
  • Incorrect gain setting.
  • Poor quality audio source.
  • Reduce volume on amplifier and audio source.
  • Switch the GAIN to 'L' (Low) if using low-impedance headphones.
  • Ensure audio source provides a clean signal.
Short Battery Life
  • Battery not fully charged.
  • High volume usage.
  • High impedance headphones.
  • Ensure the amplifier is fully charged before use.
  • Lower the volume if possible.
  • Consider using 'L' (Low) gain setting.

10. Specifications

Model Number ESY120uk-JP
Battery Capacity 1000mAh Lithium Polymer
Usage Time >8 hours
Internal Voltage 8.3V/1A
Signal-to-Noise Ratio (SNR) >100dB
Total Harmonic Distortion + Noise (THD+N) 0.0003%
Output Power 40mW (at 16Ω impedance)
Adapted Headphone Impedance 10-150Ω
Dimensions (L x W x H) 95 x 52 x 13 mm (3.74 x 2.05 x 0.51 inches)
Weight 140 grams
Material Aluminum
Certifications CE, RoHS
UPC 670924940555

11. Warranty and Support

For warranty information, technical support, or any inquiries regarding your ESYNiC Portable HiFi Headphone Amplifier, please refer to the contact details provided with your purchase documentation or visit the official eSynic website. Keep your purchase receipt for warranty claims.

© 2026 eSynic. All rights reserved.

Ask a question about this manual

Ask about setup, troubleshooting, compatibility, parts, safety, or missing instructions. Manuals+ will review the question and use this page’s manual context to help answer it.

After a successful submission, we securely hash the supplied account or form email before sending it to Microsoft Advertising for conversion attribution. Privacy details.