Fosi Audio K4 Mini Stereo DAC Compact Digital Amplifier User Manual

K4 Mini Stereo DAC User Manual

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Product Specifications

The K4 is a mini compact digital to analog converter, supporting USB, optical, and coaxial digital inputs, 3.5mm headphone jack, and RCA outputs, suitable for most home audio systems. With treble and bass control, it can be used as a preamplifier or volume control for PC/Mac. Fosi Audio K4 DAC ensures exquisite musicality, accurate and realistic phasing, and reproduction of the original sound!

PCM5100+MAX97220
USB Sampling Rate:| 24Bit/96kHz
Optical/Coaxial Sampling Rate:| 24Bit/192kHz
Headphone Impedance:| 16-300Ω
RCA Output Level:| 2V
Power Supply:| 5V
Power Input Interface:| USB Type-C
THD:| ≤0.001%
SNR:| ≥110dB
Size (LWH):| 4.43.71.2inch (1129530mm)
Net Weight:| 0.49pound (222g)

Product Overview & Control Functions

Package Contents

Fosi Audio K4 Mini Stereo DAC ×1
USB Type-C Cable ×1
Optical Cable ×1
User’s Manual ×1

Quick Setup

PC-Windows for example

PC/Mac USB input to K4 to headphone
Prepare: K4, PC/Mac, USB Type-C cable, Headphone.
Step 1: Connect the K4 to the PC/Mac via a USB Type-C cable;
Step 2: Connect the headphone to the 3.5mm headphone jack;
Step 3: Long press the multi-function knob till the indicator lights up to turn on the power;
Step 4: Short press the multi-function knob to select USB input mode;
Step 5: Left click the sound icon on your PC/Mac and change the sound output device to “Fosi Audio K4”;
Step 6: Turn up the volume;
Step 7: Play the music on your PC/Mac and enjoy!
NOTE 1: Please turn down the volume to the minimum before powering on the K4;
NOTE 2: The volume control knob combines the power switch and mode switch. You can long-press to turn on and turn off, short press to switch between modes;
NOTE 3: The mode selection can be memorized when you switch off the device.

Optical for example

Optical input to K4
Prepare: K4, AC adapter, USB Type-C cable, a device with optical output (TV for example), optical cable.
Step 1: Connect the USB Type-C cable to the AC adapter(or any other DC 5V phone charger or computer USB connector), then connect the USB Type-C cable to the K4;
Step 2: Connect the TV to K4’s optical port via the optical cable;
Step 3: Set the TV’s optical output sound type to RAW/PCM;
Step 4: Long press the multi-function knob to switch on K4;
Step 5: Short press the multi-function knob to select OPT input mode;
Step 6: Turn up the volume and enjoy!

NOTE: Some devices’ default sound output is of Dolby or DTS type, which K4 DOES NOT support. Please remember to select RAW/PCM sound type on your device, otherwise, you will hear a lot of noise or no sound output.

Coaxial for example

Coaxial input to K4
Prepare: K4, AC adapter, USB Type-C cable, device with coaxial output(TV for example), coaxial cable (not included in the package).
Step 1: Connect the USB Type-C cable to the AC adapter(or any other DC 5V phone charger or computer USB connector), then connect the Type-C cable to the K4;
Step 2: Connect the TV to K4’s coaxial port via the coaxial cable;
Step 3: Set the TV’s coaxial output sound to RAW/PCM;
Step 4: Long press the multi-function knob to switch on K4;
Step 5: Short press the multi-function knob to select COA input mode;
Step 6: Turn up the volume and enjoy!
NOTE: Some devices’ default sound output is of Dolby or DTS type, which K4 DOES NOT support. Please remember to select RAW/PCM sound type on your device, otherwise, you will hear a lot of noise or no sound output.

Troubleshooting/QA

1: How do I power on the K4 Mini stereo DAC?

• Besides the USB Type-C cable included in the package, you’ll also need a 5V power adapter with USB output, such as your cell phone’s charger or power bank.
  Note: When you plug the USB Type-C cable into the K4 and hear the “click” sound, that means the connection is up. Please do not intend to insert the cable to K4’s USB/POWER port fully which can cause damage.

2: Why is it that all my cables are plugged in well, but the K4’s RCA analog output is still silent?

• Please check if the input mode selection is correct.
• The K4 supports 3.5mm headphone output and RCA sound output simultaneously. You can check if the headphone output is normal or not when you find the RCA output has no sound.
• Please try to replace the RCA cable and test again.

3: Why do I get endless white noise?

• Please check that your input device is using Dolby/DTS audio,
  If so, please change it to RAW/PCM type and try again.

4: No Dolby/DTS audio and I still get noise through the USB input?

• Please try to connect the USB Type-C cable to the other USB ports on your PC. Some USB ports may have unstable data transmission so please try to swap it;
• Please try again on another computer;
• Please replace the USB Type-C cable and retest;
• Select Start, then type device manager in the Search box, and then select Device Manager;

5: The K4 is not recognized on Windows?

• Click Start menu, then type device manager in the Search box and then select Device Manager;
• Expand Universal Serial Bus controllers. Press and hold (or right-click) a device and select Uninstall. Repeat for each device;
• Once complete, restart your computer. Your USB controllers will automatically install.
• If Windows update causes the device to be unrecognized, please update all windows components and reboot and retest. Please contact us if the problem still insists.

6: How to do plug-and-play on Windows?

• Just click the sound icon in your notification area;
• Click the “Select playback device” option;
• Select the playback device “Fosi Audio K4”.

7: I can’t play Spotify music in Plug-and-Play mode?

• Please exit the Spotify app and switch the playback device to the computer’s own sound card device, open Spotify and play, confirm that it works, and then switch the playback device to DAC-K4 “Fosi Audio K4”

8: How do I get the highest 24Bit/96kHz resolution on my PC?

• Right-click the PC sound icon in the right bottom notification area, open Volume Mixer, click the icon of the device/SPDIF: “Fosi Audio K4” to open the Properties, click the Advanced, select 24Bit/96kHz for maximum sound quality output.

9: Why do I get an intermittent sound?

• Please try to connect the USB Type-C cable to the other USB ports on your PC. Some USB ports may have unstable data transmission. Normally speaking it’s better to use the USB port on the rear panel of the computer console;
• Please replace the USB Type-C cable and retest. Contact us if the problem still insists.

10: Why did my device stop working after a short time of use?

• Make sure your audio source and the headphones, amplifier, or active speakers you connect are working well. And please check over all the connections of the input and output cables. Then you can try to change the audio input source, output devices, and cables to test again. Also please check if the power supply works or not.

If you have any other problems, please refer to our technical support emails.

Comparison Section

3.5mm Headphone+RCA
Treble & Bass Control| Yes| Yes| No| Yes
Size| 4.43.71.2inch| 3.63.91.4inch| 3.72.80.9inch| 4.33.91.2inch

Warranty Information

• All Fosi Audio products have an 18-month limited warranty on parts and labor from the date of purchase. Please contact us if you have any problems.

About Fosi Audio

• Fosi Audio designs and builds innovative audio products with all your music in mind. Great sound, simple but elegant designs, high-quality materials, and truly useful features are what Fosi Audio is about. We sincerely hope you get as much enjoyment from our products as we’ve had to create them!

Our website: www.fosiaudio.com
Amazon store: www.amazon.com/fosiaudio
Our Youtube channel: Fosi Audio
Our Facebook page: Fosi Audio

After-sale Service and Technical Support Email:
sale@fosiaudio.com
support@fosiaudio.com
customer@fosiaudioshop.com

https://h5.shengcai.net/wwei/url?url=H666G_V7w6G
Fosi Audio Product’s User Manual

Documents / Resources

| Fosi Audio K4 Mini Stereo DAC Compact Digital Amplifier [pdf] User Manual
K4, Mini Stereo DAC Compact Digital Amplifier, K4 Mini Stereo DAC Compact Digital Amplifier
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