FOSI Audio ZH3 Review

 

Introduction:

The FOSI Audio Audio ZH3 is a compact yet powerful Desktop DAC, Headphone Amplifier/Preamp, and preamp, crafted to deliver high-fidelity audio for both casual listeners and discerning audiophiles. Equipped with an AKM4493SEQ DAC chip, XMOS XU316 USB controller, and four OPA1612 operational amplifiers, the ZH3 promises pristine audio reproduction with a fully balanced architecture. Its versatility shines through a comprehensive set of inputs (USB, Optical, Coaxial, RCA) and outputs (4.4mm balanced, 6.35mm single-ended, RCA, XLR), alongside thoughtful features like a 1.5-inch LCD display and remote control for seamless operation. Designed to drive headphones ranging from 16 to 300Ω, it offers substantial power, particularly through its balanced output, making it a compelling choice for those seeking an all-in-one audio solution.

This review explores the ZH3’s design, build quality, connectivity, and, most importantly, its sonic performance, with a focus on its synergy with the Fosi Audio i5 and HiFiMAN Sundara CB headphones. Whether you’re building a desktop audio setup or seeking a hub for a larger HiFi system, the ZH3 aims to deliver exceptional value without compromising on quality.

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 ZH3 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 ZH3 is currently available for $199.99 USD. More information’s can be found under the link below;

• FOSI Audio ZH3 DAC & Headphone Amplifier/Preamp

 

Package & Accessories:

The FOSI Audio ZH3 comes inide a rectangulat box. The box has a white carboard sleave with the ZH3 illusration and some product related barndings on the top. The actual box inside is also in white with a silver “HEAR THE UNHEARD” motto printed on it, presenting Clean and minimalistic design. The contents are securely packed in custom foam inserts to ensure safe delivery.

The package includes:

• 1 x Fosi Audio ZH3 DAC & Headphone Amplifier/Preamp
• 1 x USB-A to USB-C cable (with a convenient pull-tab for easy removal)
• 1 x 6.35mm to 3.5mm headphone adapter
• 1 x 12V trigger cable
• 1 x DC 12V power supply
• 1 x IR remote control
• 1 x Extra Volume Wheel with FOSI Audio logo
• 1 x User manual

The inclusion of a trigger cable, a thoughtfully designed USB cable with a pull-tab, and the extra black volume wheel with the FOSI Audio logo demonstrates attention to detail, enhancing the unboxing experience. 

 

Design & Build Quality:

The FOSI Audio ZH3 features a chassis made from a single piece of CNC-machined aluminum alloy, which provides a solid and durable build suitable for a device in the $199 price range. Its dimensions are 16.2 cm (width) x 15 cm (depth) x 5 cm (height), allowing it to fit on a crowded desk or within a larger audio setup without requiring excessive space.

The matte black finish is achieved through an anodized process, giving the surface a uniform appearance, while the orange volume knob serves as a practical visual indicator.

The front panel is organized for practicality.

At the left side is a 1.5-inch circular LCD display clearly shows the input source, sampling rate, volume level, and filter settings, making it easy to monitor during use.

To the right of the display, the 6.35mm single-ended and 4.4mm balanced headphone outputs are positioned side by side, with the included 3.5mm adapter adding versatility.

Further to the right, the multifunctional orange volume knob handles power, volume, and menu navigation with a firm click; a single press enters the menu, a double press exits, and a long press turns the unit off, though it may take some familiarity to master.

The rear panel is designed for connectivity, featuring a DC 12V power input on the left, followed by a 12V trigger in/out port for system integration. Next are the digital inputs: a USB-C port, an Optical input, and a Coaxial input, all clearly labeled. To the right, RCA line-in and line-out ports support analog connections, while XLR balanced outputs cater to preamp use.

The ports are spaced to accommodate various cable sizes, and the labeling aids in setup.

Overall, the ZH3 offers a practical design and build quality that align with its $199 price, providing a functional and durable option for audio enthusiasts.

 

Technical Specifications:

 

General Specifications: 

• Model: ZH3
• Chipset: XMOS XU316, AKM4493SEQ, OPA1612 x 4
• Impedance: 16–300Ω
• Input: Coaxial, Optical, USB, RCA
• Output: 4.4mm Balanced, 6.35mm Single-Ended, RCA, XLR
• Power Input: DC 12V
• Maximum Sampling Rates:
  • USB: PCM 32bit/768kHz, DSD512
  • Optical: PCM 24bit/192kHz
  • Coaxial: PCM 24bit/192kHz

4.4mm Balanced Headphone Output:

• Max Output Power: 2570mW x 2 at 32Ω, THD+N < 1%
• SNR: ≥ 119 dB
• Dynamic Range: ≥ 119 dB
• THD: ≤ 0.00018%
• Noise Floor: ≤ 4.9 μV

6.35mm Single-Ended Headphone Output:

• Max Output Power: 640mW x 2 at 32Ω, THD+N < 1%
• SNR: ≥ 121 dB
• Dynamic Range: ≥ 121 dB
• THD: ≤ 0.00024%
• Noise Floor: ≤ 1.9 μV

RCA/XLR Preamp Output:

• Output Level: >2Vrms (RCA), >4Vrms (XLR)
• SNR: ≥ 119 dB
• THD: ≤ 0.0002%
• Dynamic Range: ≥ 119 dB

Frequency Response (All Outputs): 20Hz-20kHz (±0.1dB)

 

Hardware Features:

DAC & Amplifier Sections:

The ZH3 is equipped with the AKM4493SEQ DAC chip, a high-performance digital-to-analog converter known for its exceptional clarity and support for high-resolution audio formats. This chip supports PCM up to 32-bit/768kHz and native DSD512 via USB, with Optical and Coaxial inputs handling up to 24-bit/192kHz. The AKM4493SEQ is designed with a low-distortion architecture, achieving a total harmonic distortion (THD) of less than 0.00015% and a signal-to-noise ratio (SNR) exceeding 120dB, which contributes to its clean and accurate sound reproduction. Its dynamic range of over 120dB ensures fine detail retrieval, making it suitable for critical listening.

In the ZH3, the DAC is paired with the XMOS XU316 USB controller, which ensures precise asynchronous USB audio processing and reduces jitter to enhance timing accuracy. The implementation includes a fully balanced signal path, leveraging the DAC’s differential outputs to minimize noise and crosstalk. The 1.5-inch LCD display provides real-time feedback on the sampling rate, allowing users to confirm the resolution of the incoming audio—such as 44.1kHz for standard CDs or 768kHz for high-resolution files. This combination of hardware and design makes the ZH3’s DAC section a robust foundation for its audio performance, delivering a transparent and detailed output that aligns with its $199 price point.

 

The ZH3 features four OPA1612 operational amplifiers in a fully balanced, complementary push-pull design, providing robust power output. The 4.4mm balanced output delivers 2570mW per channel at 32Ω, making it capable of driving demanding headphones with ease. The 6.35mm single-ended output, while less powerful at 640mW per channel, is suitable for less demanding headphones and IEMs. Eleven ultra-low-noise LDO regulators and precision components minimize distortion (THD ≤ 0.00018% on balanced) and noise floor (≤ 1.9 μV on single-ended), ensuring a pristine signal path. The ZH3 supports headphones from 16 to 300Ω, offering versatility for various audio gear.

 

Digital Filters:

The ZH3 provides six digital filter options: Precise Analytical, Powerful Dynamic, Neutral Balanced, Extended Highs, Well Defined, and Natural Smooth. These filters allow subtle adjustments to treble roll-off and impulse response, enabling users to tailor the sound to their headphones and preferences.

Connectivity: 

The ZH3’s connectivity options make it a versatile centerpiece for audio setups.

The rear panel includes:

• USB-C supporting high-resolution PCM and DSD
• Optical and Coaxial inputs, up to 24bit/192kHz
• RCA line-in for analog sources
• RCA and XLR preamp outputs
• 12V trigger in/out for system integration

The front panel features:

• 4.4mm balanced headphone output
• 6.35mm single-ended headphone output with a 3.5mm adapter included

The remote control simplifies input switching and filter adjustments, while the trigger connectivity enables seamless integration with other FOSI Audio components, such as the ZP3 preamp or V3 Mono amplifiers, making the ZH3 an ideal hub for a cohesive audio ecosystem.

User Scenarios:

The ZH3 caters to a variety of use cases. Headphone enthusiasts benefit from its powerful balanced output and clean amplification, ideal for driving high-impedance headphones or sensitive IEMs. Audiophiles appreciate the high-resolution DAC and filter options for customizing sound. As a preamp, the ZH3 integrates effortlessly into speaker-based systems, with XLR outputs ensuring compatibility with high-end amplifiers. Its compact size and intuitive controls make it suitable for both desktop and home HiFi setups.

 

Equipment’s used for this review:

• DAC/AMP: FOSI Audio ZH3
• Sources:  MSI Vector GP68 HX
• Headphones: FOSI Audio i5, HiFiMAN Sundara CB

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 ZH3 delivers a transparent, neutral sound signature that preserves the natural character of recordings, allowing headphones to perform as intended. Its clean amplification and high-resolution DAC ensure exceptional detail and clarity, making it suitable for both critical listening and relaxed enjoyment. After a burn-in period of approximately 50 hours, I evaluated the ZH3 using its 4.4mm balanced output without EQ, paired with the FOSI Audio i5 and HiFiMAN Sundara CB headphones. The following impressions highlight the ZH3’s performance across various genres and its synergy with these headphones.

Bass:

The ZH3’s bass performance is precise, controlled, and impactful, offering a balance of depth and clarity that enhances a wide range of music. When paired with the FOSI Audio i5, a dynamic driver headphone, the ZH3 produces tight, well-defined lows that avoid any hint of muddiness. Listening to Massive Attack’s “Angel,” the sub-bass frequencies were deep and resonant, providing a solid foundation that enveloped the listener without overwhelming other elements. In Red Hot Chili Peppers’ “Nobody Weird Like Me,” the ZH3 maintained clarity during complex basslines, delivering each note with punch and precision, enhancing the track’s dynamic energy.

With the HiFiMAN Sundara CB, a planar magnetic headphone, the ZH3 elevates the bass to a new level of richness and texture. In Isaac Hayes’ “Walk On By,” the low-end warmth was rendered with a layered, soulful quality that complemented the track’s emotional depth. The ZH3’s 2570mW balanced output provides ample power to drive the Sundara CB’s planar drivers, resulting in a bass response that feels both authoritative and refined. The bass tone control allows subtle adjustments for headphones needing a boost, though the i5 and Sundara CB performed admirably with minimal tweaking due to the ZH3’s inherent control.

Midrange:

The ZH3’s midrange is a highlight, delivering exceptional clarity, natural timbre, and a neutral presentation that excels with vocals and instruments. Paired with the FOSI Audio i5, the ZH3 reproduces vocals with striking fidelity. In Sarah McLachlan’s “Angel,” her voice was rendered with emotional clarity, capturing every nuance and breath with intimacy. The i5’s slightly forward midrange was enhanced by the ZH3’s transparency, allowing the delicate piano accompaniment to resonate with proper weight and decay.

With the HiFiMAN Sundara CB, known for its open and detailed midrange, the ZH3 shines even brighter. In Sertap Erener’s “Aşk,” the emotional intensity of her vocals was captured with smooth, natural texture, free of harshness. Instrumental tracks like Gogo Penguin’s “Raven” showcased the ZH3’s ability to handle complex midrange elements, with the interplay of piano and double bass presented with precise separation and coherence. The ZH3’s neutral midrange ensures that both headphones retain their unique character, making it an ideal partner for revealing the true essence of your gear.

Treble:

The ZH3’s treble is smooth, extended, and detailed, delivering clarity without fatigue. With the FOSI Audio i5, the treble in Diana Krall’s “So Wonderful” was airy and refined, with cymbals and high-pitched vocals rendered with a natural sparkle. The ZH3 avoids sibilance, ensuring comfortable listening over long periods. The treble tone control allowed subtle boosts to enhance the i5’s highs, adding crispness to tracks like Sting’s “Englishman in New York,” where hi-hats and brass elements gained a touch of vibrancy.

The HiFiMAN Sundara CB, with its bright and detailed treble, pairs exceptionally well with the ZH3. In Vivaldi’s “The Four Seasons,” the violin passages were crystalline and articulate, each note precisely defined. The ZH3’s “Precise Analytical” filter enhanced the treble’s precision, making the Sundara CB’s high-frequency response feel even more refined, while the “Natural Smooth” filter softened the edges for a more relaxed presentation. This flexibility allows the ZH3 to adapt to various listening preferences and headphone characteristics.

Soundstage & Imaging:

The ZH3 provides a commendable soundstage and imaging, particularly through its balanced output. With the FOSI Audio i5, the soundstage in Rush’s “YYZ” was adequately wide, with clear separation between guitar, bass, and drums. The ZH3’s imaging ensured precise instrument placement, creating an engaging and cohesive soundscape. While the i5’s soundstage is somewhat intimate, the ZH3 maximizes its potential, adding depth to tracks like Max Richter’s “On the Nature of Daylight.”

The HiFiMAN Sundara CB, renowned for its expansive soundstage, truly excels with the ZH3. In Sonya Yoncheva’s “Il Trovatore, Act I,” orchestral elements were spread across a wide, three-dimensional stage, with the ZH3’s balanced output delivering pinpoint imaging. The precise positioning of strings, brass, and vocals created a concert-hall-like experience. The ZH3’s ability to drive the Sundara CB’s planar drivers enhances its spatial capabilities, making it ideal for orchestral and cinematic tracks like Bear McCreary’s “Valkyries” from the God of War OST.

 

Synergy :

The ZH3’s synergy with the FOSI Audio i5 is impressive, offering a budget-friendly yet high-performing setup. The i5’s dynamic driver benefits from the ZH3’s clean power, with the balanced output unlocking a fuller, more dynamic sound. Tracks like Metallica’s “Sad but True” showcased the i5’s ability to handle aggressive bass and midrange riffs, with the ZH3 providing the drive to keep the sound tight and impactful. The i5’s slightly warm signature is complemented by the ZH3’s neutrality, ensuring a balanced and engaging listen across genres.

The HiFiMAN Sundara CB, with its planar magnetic design, is where the ZH3 truly shines. The 2570mW balanced output provides ample headroom to drive the Sundara CB, revealing its open and detailed sound. In David Bowie’s “Heroes,” the ZH3 enhances the Sundara CB’s airy treble and wide soundstage, creating an immersive experience that rivals more expensive setups. The ZH3’s low noise floor (≤ 4.9 μV on balanced) ensures that quiet passages in Chopin’s “Nocturne No. 20” remain free of hiss, allowing the Sundara CB’s micro-details to stand out. This combination is ideal for audiophiles seeking high-end performance on a budget.

 

Conclusion:

The FOSI Audio ZH3 is an exceptional all-in-one DAC, headphone amplifier, and preamp that delivers outstanding performance for its $199 price point. Its CNC-machined aluminum chassis, vibrant LCD display, and intuitive controls offer a premium user experience, while its versatile connectivity makes it a flexible hub for any audio setup. The AKM4493SEQ DAC, XMOS XU316 processor, and OPA1612 amplifiers ensure high-fidelity audio, with the balanced output providing ample power for demanding headphones.

Sonically, the ZH3 offers a neutral, transparent sound that pairs beautifully with both the FOSI Audio i5 and HiFiMAN Sundara CB. Its precise bass, clear midrange, and smooth treble make it suitable for a wide range of genres, from jazz and classical to rock and electronic. The digital filters add customization options, allowing users to tailor the sound to their preferences. While the single-ended output is less powerful and tone controls can be slow to adjust, these are minor drawbacks in an otherwise stellar package.

For audiophiles and casual listeners alike, the ZH3 offers a compelling blend of advanced engineering, robust build quality, and versatile functionality. Whether driving budget-friendly headphones like the i5 or high-end planars like the Sundara CB, the ZH3 delivers performance that exceeds expectations, making it a standout choice for any desktop audio system.

 

 

Pros & Cons:

• + Compact, elegant design with circular LCD display
• + Versatile connectivity including USB, Optical, Coaxial, RCA, XLR, and 12V trigger
• + Powerful 4.4mm balanced output with 2570mW x 2 at 32Ω
• + Neutral, transparent sound signature
• + Excellent synergy with FOSI Audio i5 and HiFiMAN Sundara CB
• + Six digital filters for sound customization
• + Low noise floor and distortion for clean audio
• + Remote control for convenient operation

 

• – Single-ended 6.35mm output less powerful with 640mW x 2 at 32Ω
• – Tone control adjustments are slow and less precise than software EQ
• – No XLR headphone output

 

Thank you for the Read!