Fosi Audio K5 User manual

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Fosi Audio K5 User Manual

Product Specifications
The K5 is a mini stereo gaming DAC headphone amplifier with
microphone, supporting USB Type-C, 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 K5 DAC ensures exquisite musicality, accurate and
realistic phasing, and reproduction of the original sound!
Output Type: 3.5mm Headphone, RCA
Optical/Coaxial
Sampling Rate:
24Bit/192kHz
Input Type: USB Type-C, Optical,
Coaxial, Microphone
USB Sampling Rate: 24Bit/96kHz
Headphone Impedance: 16-300Ω
RCA Output Level: 2V
Power Supply: 5V
THD: ≤0.001%
Power Input Interface: USB Type-C
SNR: ≥110dB
Size (L*W*H): 4.4*3.7*1.2inch (112*95*30mm)
Net Weight: 0.55lb/251g

Product Overview & Control
Functions
USB Type-C/
DC Power Input
Optical
Input Coaxial
Input
RCA Output
COA
AUDIO IN
OPT
DC 5V
AUDIO OUT
www.fosiaudio.com
USB/POWER
3.5mm headphone output
with microphone
Bass Control Mode Switch:
1.Power Switch: Long press to
turn on and turn off
2.Mode Switch: Short press to
switch between modes
3.Volume Tuning
Input Mode
Indicator Treble Control
BASS TREBLE MODE VOL
K5 MINI STEREO GAMING DAC
USB OPT COA

Package Contents
Fosi Audio K5 Mini Stereo Gaming DAC ×1
USB Type-C Cable ×1
Headset Microphone Two-in-one Adapter Cable ×1
User’s Manual ×1
Quick Setup
USB input to K5 to a headphone or powered speakers
Prepare: K5, PC, USB Type-C cable, the Headset Microphone
Two-in-one Adapter cable, headphones, or powered
speakers.
Step 1: Connect the K5 to the PC via a USB Type-C cable;
Step 2: Connect the headphone to the K5 by the Headset
Microphone Two-in-one Adapter cable or connect the
powered speakers to K5 by the RCA output;
NOTE: If your headphone hasn’t microphone or you don’t need to
say anything, you don’t need the Two-in-one Adapter cable
to connect, you can connect the headphone directly.
USB Input for example
Step 2Step 1 Step 3
K5 Lights
multi-function
knob
Step 7
Enjoy it!
Step 6
Turn up
Step 5
“Fosi Audio K5”
PC
Step 4
multi-function
knob
USB
K5 PC/Mac
USB Type-C
cable

Step 3: Long press the multi-function knob till the Input Mode
Indicator lights up to turn on K5;
Step 4: Short press the multi-function knob to select USB input
mode, the USB input mode light will stay on blue;
Step 5: Left click the sound icon on your PC and change the
sound output device to “Fosi Audio K5”;
Step 6: Turn up the volume;
Step 7: Play the music on your PC and enjoy!
NOTE 1: Please turn down the volume to the minimum before
powering on the K5;
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.
NOTE 4: The K5 can’t connect the passive speakers directly. If you
want to connect passive speakers, you need to connect an
amplifier first, and the connect the passive speakers.
Optical/Coaxial Input for example
AC adapter K5
USB Type-C
cable
multi-function
knob
Step 5
multi-function
knob
OPT
or
COA
Step 2
Step 1
Step 3
RAW/PCM
TV
OPT or COA
Enjoy it!
Step 6 Step 4

Step 3: Long press the multi-function knob till the Input Mode
Indicator lights up to turn on K5;
Step 4: Short press the multi-function knob to select USB input
mode, the USB input mode light will stay on blue;
Step 5: Left click the sound icon on your PC and change the
sound output device to “Fosi Audio K5”;
Step 6: Turn up the volume;
Step 7: Play the music on your PC and enjoy!
NOTE 1: Please turn down the volume to the minimum before
powering on the K5;
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.
NOTE 4: The K5 can’t connect the passive speakers directly. If you
want to connect passive speakers, you need to connect an
amplifier first, and the connect the passive speakers.

Optical/Coaxial input to K5
NOTE: In optical and coaxial input mode, the K5 does not support
microphon.
Prepare: K5, AC adapter, USB Type-C cable, device with optical
output (TV for example), optical cable or 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 USB Type-C cable to the K5;
Step 2: Connect the TV to K5's optical port via the optical cable;
(Connect the TV to K5's coaxial port via the coaxial 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 K5;
Step 5: Short press the multi-function knob to select OPT or COA
input mode;
Step 6: Turn up the volume and enjoy!
NOTE: Some devices’ default sound output is of Dolby or DTS
type, which K5 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: No sound from the microphone.
• Please make sure all cables are well connected.
• Please make sure your headphone support the microphone,
some headphone does not support the microphone. PC default
path: Setting-Microphone-Allow accessing to your microphone
• Please make sure the Record on your PC sound settings is set to
“Fosi Audio K5”. PC default path: Sound settings-Record-Choose
“Fosi Audio K5”.

• Please make sure the K5 is in USB input mode. In optical and
coaxial input mode, the K5 does not support microphone.
• Please make sure the microphone permission has been turned on
on the audio source device
• Replace another Headset Microphone Two-in-one Adapter Cable
to have a try.
2: How do I power on the K5 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 K5 and see the
input Mode Indicator is lighting up, which means the
connection is up. Please do not intend to insert the cable to
K5’s USB/POWER port fully which can cause damage.
3: Why do I get endless white noise?
• Please check if the input mode selection is correct.
• The K5 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.
4: 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.
5: 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;
6: The K5 is not recognized on Windows?
• Select Start, then type device manager in the Search box, and
then select Device Manager;
• 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.
7: 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 K5”..
8: 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-K5 “Fosi Audio K5”
9: 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 K5” to open the Properties, click the Advanced, select

24Bit/96kHz for maximum sound quality output.
10: Why do I get an intermittent sound via the USB
connection?
• 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.
11: Why cuts the sound in or out?
• Try to reduce the sound of your device.
• Try to exchange your audio source and cables test, if still so then
there are problems with the K5.
12: Why does 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.
For any problems please leave a message to the customer
support email address: [e-mail]

Comparison Section
K5
Input USB+Optical+
Coaxial
Bluetooth 5.0+
PC-USB+
Optical+
Coaxial
USB Type-C+
Optical+
Coaxial
USB Type-C+
Optical+
Coaxial+
Microphone
Output 3.5mm
Headphone+
RCA
3.5mm
Headphone+
RCA
3.5mm
Headphone+
RCA
3.5mm
Headphone+
RCA
3.5mm
Headphone+
RCA
Treble &
Bass Control
Yes No Yes Yes Yes
Model
Bluetooth
Version
- Bluetooth 5.0 Bluetooth 5.0 -
Picture
Bluetooth 5.0+
PC-USB+
Optical+
Coaxial
-
Headphone
Output
Impedance
16-200 (Ω) 16-300 (Ω) 16-300 (Ω) 16-300 (Ω) 16-300 (Ω)
Q4 K1 K2 K4 K5

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: 
[e-mail]
[e-mail]
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!
Fosi Audio Product’s User Manual