Fosi Audio K7 Review
Fosi Audio K7 Review
Introduction:
The Fosi Audio K7 is a versatile DAC/Amplifier designed for both gaming and audiophile applications. Featuring interesting hardware components, the K7 incorporates the AKM AK4493S DAC chip for digital-to-analog conversion, the OPA1612 amplifier for improved positional audio, and the robust TPA6120 amplifier for powering both low and high-impedance headphones. The XMOS XU208 USB controller reduces lag for synchronized audio-visual experiences, while the Qualcomm QCC3031 Bluetooth chip supports aptX HD and aptX LL codecs for high-quality, low-latency wireless audio.
The K7’s fully balanced circuitry and multiple LDO regulators work to minimize noise and enhance clarity, supported by triple intelligent protection circuits for reliable performance. Connectivity options include Bluetooth, Optical, Coaxial, RCA, and USB-C inputs, along with 3.5mm single-ended and 4.4mm balanced headphone outputs. Additionally, a dedicated 3.5mm microphone input with noise reduction ensures clear communication. The 1.5-inch LCD display and shortcut buttons provide intuitive control.
This review will cover its build quality, user interface, connectivity options, and most importantly, its sonic characteristics across different genres and use cases.
Disclaimer:
I would like to thank Fosi Audio for providing me the K7 as review sample. I am not affiliated with Fosi Audio beyond this review and these words reflect my true and unaltered, opinions about the product.
Price & Availability:
The Fosi Audio K7 is currently available through crowdfunding platforms like Kickstarter and Makuake. During this crowdfunding phase, you can secure a K7 at a discounted price. Early bird pledges start around $140, while later pledges may go up to approximately $165. It’s important to remember that these crowdfunding prices are generally lower than the expected retail price, which is estimated to be under $199. Once the crowdfunding campaign concludes, the price of the K7 is likely to increase. So, if you’re interested in the K7, backing the project now offers the best opportunity to get it at a lower cost.
More information’s can be found under the link below;
Package & Accessories:
The Fosi Audio K7 came inside a relative large rectangular black box with some an illustration and some brandings and their motto “Redefining HiFi with Unmatched Value” on the top.
Inside the box of the Fosi Audio K7 Pro are the following items:
- 1 x Fosi Audio K7 DAC/Amplifier
- 1 x USB-A/C to USB-C cable
- 1 x Bluetooth Antenna
- 1 x DC 12V Power Supply
- 1 x 3.5mm Headphone Splitter
- 1 x User Manual
Design & Build Quality:
Upon unboxing the Fosi Audio K7 desktop DAC/Amplifier, I noticed its solid construction and straightforward design. The device is made from an all-aluminum alloy, giving it a sturdy feel. The CNC integrated design adds to its durability, making it a reliable addition to any audio setup.
The minimalist design and clean lines provide a modern look, making the K7 functional and visually neutral. The side view highlights its compact design, with an angled profile that allows it to fit on a desktop without taking up much space. This is beneficial for users with limited desk space, as it sits comfortably without being intrusive. The smooth lines of the side view contribute to the overall appeal of the K7, making it a neat addition to any workspace.
Looking at the top view of the Fosi Audio K7, the dual control knobs are easy to access and use. The left knob, labeled as Vol/Gain, allows for volume adjustment and gain switching between high and low modes for headphone output. This knob can be both rotated and pressed, providing flexibility in controlling the device.
Similarly, the right knob, labeled as CTRL/Mic, adjusts bass, treble, and microphone volume, and can be pressed to mute/unmute the microphone. Next to these knobs is a 1.5-inch LCD display, which provides information such as the sampling rate, input source, and volume level.
The buttons below the knobs have specific functions: the leftmost button powers the device and switches UAC modes, the INPUT button changes input modes, the OUTPUT button toggles between headphone and RCA outputs, the BYPASS button enables/disables EQ effects, and the TONE/MIC button switches control modes for bass, treble, and microphone. This comprehensive control layout ensures users can easily manage the device’s various functions, making the Fosi Audio K7 a versatile and user-friendly DAC/Amplifier.
The front view of the K7 shows a variety of input and output ports. It includes a 3.5mm single-ended headphone output, a 4.4mm balanced headphone output, and a 3.5mm microphone input. These ports ensure compatibility with a wide range of audio equipment. The arrangement of these ports is designed for easy access while keeping the front panel organized.
Turning to the rear view of the Fosi Audio K7, the connectivity options are clear. The back panel includes ports for Bluetooth input, optical input, RCA output, coaxial input, USB-C input, and a DC 12V power input. Each port is clearly labeled, making it easy to connect various audio sources and devices. This range of inputs and outputs enhances the overall functionality of the K7, allowing for integration with multiple devices and audio setups.
Overall, the Fosi Audio K7 offers a good blend of design, build quality, and functionality.
Technical Specifications:
- Model : K7
- Chipset : XMOS XU208 + AKM4493SEQ + QCC3031 + TPA6120
- Impedance : 16-300Ω
- Input : Coaxial, Optical, USB-C, Bluetooth, 3.5mm Microphone
- Output : RCA, 3.5mm Single-Ended, 4.4mm Balanced
- FW Upgrade : XMOS firmware can be updated via the Type-C interface
- BT Version : 5.0
- BT Distance : ≤13m
- Noise Floor : ≤2.5μV
- BT Codec’s : SBC, AAC, aptX, aptX HD, aptX LL
- Input Voltage : DC 12V
- Input Current : 2A
- Compatibility : Windows 7, 8, 8.1, 10, 11 (Driver Required); Mac OS X, Linux (No Driver)
4.4mm Balanced Output:
- Rated Power: L+R 2100mW + 2100mW (32Ω/THD+N<1%)
- SNR: 121dB
- THD+N: <0.0002%
- Dynamic Range: 121dB
- Noise Floor: ≤6.5μV
3.5mm Single-Ended Output:
- Rated Power: L+R 600mW + 600mW (32Ω/THD+N<1%)
- SNR: 122dB
- THD+N: 0.0005%
- Dynamic Range: 121dB
- Noise Floor: ≤2.5μV
RCA Output:
- Output Level: >2Vrms
- SNR: 121dB
- THD+N: 0.0005%
- Dynamic Range: 121dB
Frequency Response (All Outputs): 20Hz-20kHz (±0.1dB)
Hardware Features:
The Fosi Audio K7 includes several harware components that contribute to its audio performance. Lets take a closer look.
DAC Section:
The Fosi Audio K7 features the AKM AK4493SEQ DAC chip, known for its performance and ability to handle high sampling rates and bit depths.
The specifications for the AKM AK4493SEQ DAC chip include:
Maximum Sampling Rate:
- USB: PCM 384kHz-32bit/DSD256
- Optical: PCM 24bit/192kHz
- Coaxial: PCM 24bit/192kHz
- Bluetooth: PCM 24bit/48kHz
Support for Various Audio Formats: Including PCM and DSD
Amplifier Section & Power Output:
The amplifier section of the Fosi Audio K7 includes the Texas Instruments TPA6120 amplifier, which provides power output for both low and high-impedance headphones. The Texas Instruments OPA1612 amplifier enhances positional audio. The device uses multiple low-dropout (LDO) regulators to ensure clear sound quality by providing pure power output. These LDO regulators support various components, including the OPA1612 and NJW119A. The inclusion of over-voltage protection (OVP) further ensures the safety and reliability of the power supply system. The K7’s balanced circuitry achieves low distortion of 0.0002%, reducing noise and interference. The K7 supports headphone impedance ranging from 16 to 300Ω, making it versatile for various types of headphones.
The Fosi Audio K7 offers power output suitable for a variety of headphones. It provides 600mW+600mW @32Ω through the 3.5mm single-ended output and 2.1W+2.1W @32Ω through the 4.4mm balanced output. This allows it to drive both low and high-impedance headphones. The device features a Total Harmonic Distortion (THD) of 0.0002% for the 3.5mm output and <0.0002% for the 4.4mm output. It also has a Signal-to-Noise Ratio (SNR) of 122dB for the 3.5mm output and 121dB for the 4.4mm output, aiming to provide clean and accurate audio reproduction.
Connectivity:
The Fosi Audio K7 offers a variety of connectivity options. On the rear panel, you’ll find Bluetooth input, optical input, RCA output, coaxial input, and USB-C input, allowing the K7 to connect to a range of audio sources, from traditional wired connections to wireless streaming.
The front panel includes a 3.5mm single-ended headphone output, a 4.4mm balanced headphone output, and a 3.5mm microphone input, ensuring compatibility with different types of headphones and audio setups. The noise reduction feature on the microphone input aims to provide clear communication during gaming.
The Qualcomm QCC3031 Bluetooth chip supports various codecs, including aptX HD, aptX LL, aptX, AAC, and SBC. However, it does not support LDAC, which is often preferred by audiophiles. Additionally, there is a slight but noticeable latency when watching videos and gaming, which might be an issue for users who need a perfectly synchronized audio-visual experience.
User Scenarios:
The Fosi Audio K7 is designed to cater to various user scenarios. For gamers, the Bluetooth connection and audio-visual synchronization provided by the XMOS XU208 USB controller enhance the gaming experience. The amplifiers and DAC chip allow gamers to pinpoint enemy footsteps and other audio cues. Audiophiles will appreciate the sound reproduction supported by the DAC and amplifiers. The connectivity options make the K7 suitable for streaming music from various sources, including smartphones, computers, and audio players.
Equipment’s used for this review:
- Sources : Fosi K7, MSI Vector GP68 HX
- IEM’s : ArpegEar Hane, 7HZ Timeless II
- Headphones : SIVGA Anser
Albums & tracks used for this review:
- Dionne Warwick – Walk On By (Flac 16bit/44.1kHz)
- Sarah McLachlan – Angel (Flac 24bit/48kHz)
- Sertap Erener – Aşk (Flac 16bit/44.1kHz)
- Adele – My Little Love (Spotify)
- Randy Crawford – On Day I Will Fly Away (Flac 16bit/44.1kHz)
- Hayley Westenra – Odyssey Album (Dezzer HiFi)
- Edith Piaf – Non Je Ne Regrette Rien (Flac 16bit/44.1kHz)
- Diana Krall – So Wonderful (DSF)
- Aretha Franklin – I Say A Little Payer (Flac 24bit/96kHz)
- Sonya Yoncheva – (Giuseppe Verdi) II Trovatore, ActI (Flac 24bit/96kHz)
- George Michael – Don’t Let the Sun Go Down on Me (Flac 24bit/192kHz)
- David Bowie – Heroes (Flac 24bit/192kHz)
- Elton John – Rocket Man ((Flac 24bit/96kHz)
- Barry White – Just The Way You Are (Flac 24bit/48kHz)
- Isaac Hayes – Walk On By (Flac 16bit/44.1kHz)
- Sting – Englishman in New York – (Flac 24bit/48kHz)
- Eric Clapton – Wonderful Tonight (Flac 24bit/96kHz)
- B. King – Riding With The King (Tidal Hi-Fi)
- Dave Gahan – Kingdom (Tidal Hi-Fi)
- U2 – Sunday Bloody Sunday (Flac 16bit/44.1kHz)
- Muse – Hysteria (Flac 24bit/96kHz)
- Rush – YYZ (Flac 16bit/44.1kHz)
- Red Hot Chili Peppers – Nobody Weird Like Me (Flac 24bit/48kHz)
- Bro Safari, UFO! – Drama (Deezer HiFi)
- Rok Nardin – Berserks (Spotify)
- Bear McCreary – Valkyries “God of War OST” (Deezer HiFi)
- Armin Van Buuren – Vini Vici (Flac 16bit/44.1kHz)
- Daft Punk – Doin’ it Right (Flac 24bit/96kHz)
- Jo Blankenburg – Meraki (Spotify)
- Lorde – Royals (Flac 24bit/48kHz)
- Massive Attack – Angel (Flac 24bit/48kHz)
- Toutant – Rebirth (Deezer HiFi)
- Gogo Penguin – Raven (Flac 24bit/192kHz)
- Gogo Penguin – Murmuration (Flac 24bit/192kHz)
- Alboran Trio’s – Cinque Lunghissimi Minuti (Flac 16bit/44.1kHz)
- Portishead – It Could Be Sweet (Spotify)
- Max Richter – On the Nature of Daylight (Flac 24bit/96kHz)
- Charly Antolini – Duwadjuwandadu (Flac 24bit/192kHz)
- Ferit Odman – Look, Stop & Listen (Flac 24bit/192kHz)
- Chopin – Nocturn No. 20 In C-Sharp Minor (Flac 16bit/44.1kHz)
- Fazıl Say – Nazım Oratoryosu (Live) (Flac 16bit/44.1kHz)
- Vivaldi – Le QuarttroStagioni “The Four Season” (Deezer HiFi)
- Otto Liebert& Luna Negra – The River (Flac 24bit/192kHz)
- Lunatic Soul – The Passage (Flac 16bit/44.1kHz)
- Deftones – My Own Summer (Shove it) (Flac 16bit/44.1kHz)
- Metallica – Sad but True (Flac 24bit/96kHz)
- Opeth – Windowpane (Flac 16bit/44.1kHz)
- Megadeth – Sweating Bullets (Tidal Hi-Fi)
- Rush’s – Leave That Thing Alone (Flac 16bit/44.1kHz)
- Slayer – Angel of Death (Spotify)
- Liquid Tension Experiment 2 – Acid Rain (Spotify)
- Yosi Horikawa – Bubbles (Spotify)
The Sound:
The Fosi Audio K7 has a relative neutral sound signature, meaning it doesn’t enhance or diminish any specific frequency range. This neutrality ensures that headphones and IEMs perform as intended, preserving the original character of the recordings. The K7 offers a clean, uncolored sound suitable for various genres and listening preferences. It’s a practical choice for those who want an accurate representation of their music without added coloration. The neutrality allows the K7 to work well in different settings, from casual listening to more focused audio tasks.
Please note that this review has been written after a burn-in period of about 50 hours. My sound experience below is primarily based on the 4.4mm balanced output without the use of any EQ settings, paired with in-ear monitors like the ArpegEar Hane and 7HZ Timeless II, and headphones like the SIVGA Anser.
Bass:
The Fosi Audio K7 offers good control and depth in the bass. It prevents the bass from becoming muddy or overpowering. For example, using the SIVGA Anser headphones, the bass was tight and well-defined, providing deep lows without overshadowing the mids and highs. The bass EQ feature allows you to adjust the bass response to your liking. This can be useful for headphones that may lack bass or for listeners who prefer a more pronounced low-end. However, the EQ adjustments are not as precise as those in dedicated software EQs. The K7 handles complex bass lines and sub-bass frequencies effectively. Additionally, it maintains clarity and detail even at higher volumes, which is crucial for tracks with heavy bass presence. This ensures that the bass remains impactful but doesn’t dominate the overall sound.
Midrange:
The midrange performance of the Fosi Audio K7 is neutral and clear. Vocals and instruments sound natural and well-defined. With the ArpegEAr Hane IEMs, the midrange was balanced, neither emphasized nor recessed. This neutrality ensures that vocals and instruments are reproduced authentically. It is beneficial for genres that rely on midrange clarity, such as acoustic and classical music. The K7’s ability to reproduce the timbre and texture of midrange instruments like guitars and pianos makes it a good option for music enjoyment and audio analysis. The midrange’s clarity helps listeners appreciate the details of the performance. The device also performs well with complex midrange elements, ensuring that layered vocals and intricate instrumental passages are delivered with precision and coherence.
Treble:
The treble on the Fosi Audio K7 is smooth and detailed, avoiding harshness or sibilance. It adds air and sparkle to keep the sound engaging without becoming fatiguing. With the 7HZ Timeless II IEMs, the treble was well-extended, providing a detailed high-frequency response. The treble EQ feature allows fine-tuning of the high frequencies, useful if you’re using IEMs that are either too bright or too dark. This flexibility ensures that listeners can achieve a sound profile that suits their preferences. The K7’s treble performance enhances the clarity of cymbals, strings, and higher-pitched vocals, contributing to an enjoyable listening experience. The ability to adjust the treble ensures the sound remains dynamic and engaging. Moreover, the treble retains its detail and resolution even at higher volumes, making it suitable for listeners who enjoy a more pronounced high-frequency presence.
Soundstage & Imaging:
The soundstage provided by the Fosi Audio K7 offers a decent sense of space and instrument separation. It may not be the most immersive, but it still provides satisfactory spatial awareness. Using the SIVGA Anser headphones, the soundstage felt adequately wide, allowing for clear distinction between different elements in the audio. While the K7’s soundstage is average, it provides enough depth and dimension to make listening sessions engaging. Though it may not deliver a top-tier soundstage, it offers good performance for its price, making it a value-for-money option.
Conclusion:
The Fosi Audio K7 is a well-designed desktop DAC/Amplifier, suitable for both gaming and audiophile use. Its all-aluminum alloy body with CNC machining offers durability and a high-end feel. The compact design is practical for any setup, and the front panel’s intuitive layout, coupled with versatile connectivity options on the rear panel, enhances user experience. High-quality components like the AKM AK4493S DAC chip, OPA1612 amplifier, and TPA6120 amplifier contribute to detailed sound. The XMOS XU208 USB controller and Qualcomm QCC3031 Bluetooth chip support high-quality, low-latency wireless audio. The K7’s balanced circuitry and multiple LDO regulators aim to minimize noise and improve clarity, while the 1.5-inch LCD display and shortcut buttons provide easy control.
In terms of sound, the Fosi Audio K7 has a neutral signature, meaning it doesn’t enhance or diminish any specific frequency range. This ensures an accurate representation of recordings, suitable for various genres and listening preferences. The device offers good bass control, clear midrange, and smooth treble, making it versatile for different audio needs. The soundstage provides a decent sense of space and instrument separation. While it may not be top-tier in every aspect, the K7 offers solid performance for its price, balancing aesthetics, functionality, and advanced engineering. This makes it a practical choice for both gamers and audiophiles.
Pros & Cons:
- + Durable all-aluminum alloy body with CNC machining
- + Compact and sleek design
- + Versatile connectivity options (Bluetooth, Optical, Coaxial, RCA, USB-C)
- + Intuitive control layout with multifunctional knobs
- + Neutral sound signature
- + Good bass control, clear midrange, and smooth treble
- + 1.5-inch LCD display for easy information access
- + Suitable for both gaming and audiophile applications
- – EQ adjustments not as precise as dedicated software EQs
- – Average soundstage, not exceptionally wide
- – No LDAC support and slight but noticeable latency when watching videos and gaming
- – Not top-tier in every aspect, but offers solid performance for its price
Thank you for the Read!
