Powerful Sound, Compact Design

Mini Audio Headphone Amp

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This is something you can use every day, it's small and portable, yet powerful and tough, with an elegant look.

Small Device, Big Sound

Budget-friendly and Tough

Fosi Audio DS2 is a fantastic combination of superior sound quality and compact size, making it an ideal mini headphone amplifier.

Worry-free output

3.5mm+4.4mm Dual Headphone Outputs for both single-ended and balanced headphones. The traditional 3.5mm single-ended headphone output is widely compatible with most headphones, and a 4.4mm balanced headphone output for a more detailed audio experience.

Compatible with multiple devices and operating systems.

ESS Technology ES9018K2M

The high-performance ES9018K2M audio chip will satisfy even the most avid audiophiles.

Reliable High-Fidelity Sound

DS2 features abundant power with a high signal-to-noise ratio, low distortion and almost 0 noise. It’s low noise floor design ensures the music is heard clearly, unadulterated by interference from your home environment.

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DAC Chipset

Dual ESS ES9018K2M QUAD DAC Chips 


Output Power

SE: 120mw(32Ω) BAL: 250mw(32Ω) 


Output Type

3.5 mm headphone jack/line-out, RCA





Frequency Response

20HZ-20KHZ +/-0.5dB 



Up to 32bit/768kHz 





Dynamic Range



Headphone Impedance

16~300Ω(SE); 16~300Ω(BAL) 


Dual Headphone Outputs

3.5mm single-ended,4.4mm balanced output 


Supported Devices



Product Weight


Frequently asked questions

Have questions? We’re hereto help

1: Regarding heat and power consumption.

  • The DS2 does not have a battery and therefore consumes power from the device. When connecting the DS2 to a mobile phone or other device, please plan power consumption wisely.
  • The DS2 is small in size but has a high output power. The temperature rise is about 15°C during operation. It is normal for it to get a little warm during use.

2: About the support of DSD files in DS2.

  • To play DSD files on the Android devices, please use an APP which supports DSD files (e.g. "HiBy Music APP") and enable the exclusive USB Audio Access Mode. The DSD output option should be set to DOP or Native. DSD512 is only supported in Native mode.
  • To play DSD files on the iOS devices, please use an APP which supports DSD files (e.g. "HiByMusic APP") and set DSD output option to (Note: iOS devices cannot support DSD512 currently.)
  • To play DSD tracks on the computer, please use the software which supports DSD files (e.g. "Foobar 2000 on window or Audirvana on mac") and install the relevant application plug-ins correctly.
  • Switching tracks with different sampling rates will cause relatively obvious impulsing sound which is a normal phenomenon. It is recommended classify music files well.

3: How to use the DS2 as a USB DAC for mobile phones?

[Android-based phone]: Just use the Type-C to Type-C cable to connect the DS2 to a mobile phone (cable is included in the package).


  • A compatibility issue may occur to certain Android mobile phones or music players due to system and hardware differences.
  • Some mobile phones are required to turn on the OTG function, so as to use the DS2 For detailed settings please consult the support of mobile phones.
  • Some mobile phones may show the "non-certified Type-C digital headphone" You can ignore the message and use it normally.

[iPhone/iPad]: Please purchase an additional Lightning to Type C OTG cable to connect DS2 to iPhone / iPad / iPod.


  • Only iOS 10.0.2 and above are supported. Due to the iOS system itself, Apple devices below this version cannot be supported.
  • Since there is a limitation on the power supply to external USB devices from iPhone, DS2 with high output power may have stuttering or no sound problem at high volume.

4: How to use the DS2 as a USB DAC for computers?

[Windows system]

  • The DS2 can be used plug-and-play on window 8/10 and does not require driver installation.
  • Connect the DS2 to your computer using a Type-C to Type-C (If your computer's USB port is USB A, you can use a Type C to USB A cable to help you with this) (included in the package).
  • Select the Fosi Audio DS2 as the audio output on your


  • Macbook does not require driver installation. Select Fosi Audio DS2 directly as the output device.

5: Under what circumstances do I need to download the driver before using DS2 in window system?

  • The computer operating system is window 7.
  • To play DSD songs. (Note: but you do not need to install the driver if you are using foobar and have installed its own Waspi plug-in to play DSD songs).
  • Play PCM 768KHZ songs.
  • When the interface of your device is usb 1.0. When you encounter the above problems, please first contact Fosi Audio after-sales service to obtain the DAC driver, and install it as the instruction to enable the USB DAC function.

6: What should I pay attention to when using the 4.4 interface balanced mode?

  • Please do not use any 3.5mm to 4.4mm adapters as this may result in no sound, stuttering etc. during use.
  • It is recommended to use 4.4mm headphones directly.

7: Does the DS2 support in-line headset control or answering calls with a headset?

  • The DS2 does not support in-line remote control with a headset or answering calls with a headset.
  • When there is an incoming call, the sound is still transmitted through the phone's speaker and microphone. You can pick up the phone to make a normal call. Whether or not you unplug the DS2 will have no effect.

8: Questions about Exclusive USB Audio Access Mode.

Due to system and hardware differences in exclusive USB audio access mode, some Android phones or players may have some permission conflicts and compatibility issues.

Here is the known situations:

  • On some mobile phones or DSD playback software, the volume buttons on the DS1 body cannot be synchronised to control the volume of your mobile phone, you can control the volume directly from your mobile phone.
  • Some phone power management policies do not allow third-party apps to run in the background by default. This may cause the APP to pause in exclusive USB audio access mode after the phone has slept for a few seconds. You can manually set the app to keep working while sleeping in the phone's battery management settings.
  • Running other apps in exclusive USB audio access mode may cause lagging or no sound issues. We will continue to optimise this issue. If you are using exclusive USB audio access mode, we recommend that you focus on listening to music. Alternatively, you can exit the exclusive USB audio access mode to avoid this proble


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