Fosi Audio Q4
- Fosi Audio
Fosi Audio Q4
- Fosi Audio
$45.91
- Authorized Dealer · Tech Support · 30-Day Returns
Why it stands out
Best for
Not ideal for
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Setup guide
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What you should know
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Frequently asked questions
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Official product information provided by Fosi Audio
The following product descriptions, specifications and images are provided by the manufacturer.
Fosi Audio Q4 is a compact desktop DAC and headphone amplifier that converts USB, optical or coaxial digital audio to headphones and RCA analog output.
Volume plus bass and treble controls, 24-bit/192kHz S/PDIF decoding and support for 16–200Ω headphones make it a practical entry-level computer or TV audio upgrade.
Why it stands out
Three digital inputs
USB, optical and coaxial connections support computers, TVs, consoles and digital transports.
Headphone and RCA outputs
Listen through 3.5mm headphones or feed an amplifier and powered speakers through RCA.
Direct tone adjustment
Front bass and treble controls allow quick system tuning.
Compact plug-and-play control
Input selection and analog volume are integrated into a small desktop chassis.
Best for
- Entry-level computer audio
- TV optical PCM to headphones or stereo system
- Desktop headphones and powered speakers
- Users wanting physical bass and treble controls
Not ideal for
- Dolby or DTS bitstream decoding
- Balanced headphone systems
- Headphones above the specified 200Ω range
EMiUZEK Buying Notes
- Set TVs and consoles to two-channel PCM; Q4 does not decode Dolby or DTS.
- Inserting headphones can mute the RCA output.
- USB audio reaches 24-bit/96kHz; optical and coaxial reach 24-bit/192kHz.
Frequently asked questions
Can Q4 connect to a TV?
Yes, through optical or coaxial when the TV is set to PCM stereo.
Does it decode Dolby or DTS?
No. Use PCM output to avoid noise or silence.
Can it drive passive speakers?
No. RCA must feed an amplifier, or use powered speakers.
Can I use headphones and RCA together?
The headphone connection can mute RCA output, so treat them as alternate outputs.
Does USB need a driver?
It is generally plug-and-play on listed systems; select Fosi Audio Q4 as the playback device.
Can I connect an analog source?
No. All Q4 inputs are digital.
HOW TO CONNECT
Computer headphones
Source: PC or Mac
Connection: USB audio
Output: 3.5mm headphone
Target: 16–200Ω headphones
Note: Select Q4 as the playback device.
TV headphones
Source: Television
Connection: Optical PCM
Output: 3.5mm headphone
Target: Wired headphones
Note: Disable Dolby and DTS output.
Stereo system
Source: Computer, TV or transport
Connection: USB, optical or coaxial
Output: RCA
Target: Amplifier or powered speakers
Note: Use Q4 volume and tone controls.
Technical Specifications
Audio performance
| Feature | Specification |
|---|---|
| USB sampling | Up to 24-bit / 96kHz |
| Optical / coaxial | Up to 24-bit / 192kHz |
| Headphone output | 100mW at 32Ω |
| Headphone impedance | 16–200Ω |
| THD / SNR | ≤0.01% / ≥105dB |
| RCA output level | 2.3V |
Connections and physical
| Feature | Specification |
|---|---|
| Inputs | USB, optical, coaxial |
| Outputs | 3.5mm headphone, RCA |
| Chipset | SA9023 + CS8412 + 97220 + NE5532 |
| Power | 5V |
| Dimensions | 73.5 × 98 × 33mm |
| Weight | 251g |
Recommended System Setup
| Setup | Connection |
|---|---|
| Computer headphones | Computer → USB → Q4 → Headphones |
| TV system | TV optical PCM → Q4 → Amplifier |
| Powered speakers | Digital source → Q4 RCA → Powered speakers |
Additional Product Content
Fosi Audio product comparison
Compare the models by the differences that most affect system matching and everyday use.
| Feature | Q4 | K5 Pro | SK02 |
|---|---|---|---|
| Product position | Entry desktop DAC/amp | Gaming DAC/amp | Higher-performance desktop DAC/amp |
| USB maximum | 24-bit / 96kHz | 24-bit / 96kHz | 32-bit / 384kHz, DSD256 |
| Other digital inputs | Optical, coaxial | Optical, coaxial | Optical |
| Headphone outputs | 3.5mm | 3.5mm | 3.5mm, 4.4mm |
| Maximum headphone power | 100mW at 32Ω | 500mW at 32Ω | 755mW at 32Ω via 4.4mm |
| Microphone input | No | Yes | No |
| RCA output | Yes | Yes | No |
| Tone controls | Bass, treble | Bass, treble | No |
| Balanced output | No | No | 4.4mm |
| Best use | Simple PC/TV audio | Gaming with microphone | Hi-res desktop headphones |
What's in the box, manuals and downloads
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