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Pro-Ject Audio Systems Uni Box S3 variant 1

Pro-Ject Audio Systems Uni Box S3

Name: Pro-Ject Audio Systems Uni Box S3
Brand: Pro-Ject Audio Systems
SKU: uniboxs3
Rating: 4.5 (13 reviews)

View at Pro-Ject Audio Systems

Built-in DAC

Phono Stage

Headphone Output

Wi-Fi

Bluetooth

HDMI eARC

Dual Mono Design

App Control

Network Audio

Multi-Room Audio

Integrated amplifier with modern streaming

True Wireless Sending and Receiving
Leading WiiM OS ™ technology
New Pro-Ject Home App
Countless streaming services
Dual mono design principle
Made in Europe

Streaming done right.

The Uni Box S3 dares to break away from the norm, redefining what a modern streaming amplifier can be. While many amplifiers are dominated by deeply integrated streaming tech – compromising their core design – the Uni Box S3 takes a different path.

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Overall Score 90/100

Nicely Roasted

Pro-Ject Uni Box S3

The Uni Box S3 puts analogue purity front and centre, keeping analogue inputs fully in the analogue domain to preserve warmth, timbre and natural imaging — a point highlighted by Ian White and The Ear. It delivers a warm, well-focused midrange, tight bass and clean treble with stable stereo placement and punchy transients for its class.

Streaming duties are handled by WiiM OS with Wi‑Fi, Bluetooth 5.1, HDMI eARC and a Cirrus Logic 24/192 DAC; a dedicated MM phono stage and a full-size headphone amp make it vinyl-friendly. The compact aluminium chassis and deliberate separation of analogue and digital sections favour longevity and low internal interference.

Ideal for analogue-first listeners with efficient speakers in small-to-medium rooms, the Uni Box S3 pairs modern streaming convenience with Pro-Ject's analogue heritage, making it a strong choice for those who prioritise sound quality in a compact, feature-rich package.

Best of High End

"The Uni Box S3 is a bold statement in high-end audio, combining Pro-Ject’s analog heritage with modern streaming innovation."

The Ear

"Not only does the Uni Box S3 preserve the rich, lifelike character of analogue sound, but it is also designed with sustainability in mind."

ecoustics

"In a market full of streaming amps that digitize everything just because they can, Pro-Ject’s approach is a refreshingly purist one—although some may look at the price and wonder if Pro-Ject never got the memo."

Pros

Preserves a fully analogue signal path for analogue inputs, protecting timbre and lifelike character.
Very well appointed connectivity and streaming (WiiM OS, Wi‑Fi, Bluetooth 5.1, HDMI eARC) plus MM phono and headphone amp.
Compact, robust aluminium construction with careful analogue/digital separation for reduced interference and long-term reliability.
Surprising dynamic control and focused imaging for its power class, delivering tight transients and a convincing soundstage.

Cons

Modest output (around 40W/4Ω) limits headroom—best paired with efficient speakers and smaller rooms.
Lacks DSD and MQA support, and uses Bluetooth 5.1 rather than the newer 5.3 — potential format/connectivity limitations for some users.

Sound Quality

89/100

Dynamics

89/100

Despite modest published power (2x23W @8Ω, 2x40W @4Ω) and Class D topology, reviewers describe the amp as showing 'remarkable sonic muscle' and 'dynamic precision' (The Ear, Best of High End), while ecoustics cautions that efficient speakers are required to realize its potential. The score reflects strong transient control and punch for its power class but is capped below reference-level expectations because headroom is limited for large rooms or inefficient speakers.

Soundstage Imaging

88/100

Reviews highlight preservation of analogue detail and lifelike presentation, which translates to good imaging and a convincing soundstage (ecoustics, Best of High End). While reviewers do not hyperbolically call it 'holographic reference', they consistently report stable, well-focused images and natural spatial cues for the price/class.

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Build Quality

90/100

The Uni Box S3 is noted for a sleek, compact aluminium chassis, careful separation of analogue and digital sections, and European construction (ecoustics, The Ear), supporting durability and low internal interference. Reviewers also note thoughtful thermal/architecture choices (dual-mono influence from MaiA S3) that suggest solid component and layout choices for long-term reliability.

Features Connectivity

95/100

Very well appointed for a compact integrated: MM phono stage, 2x RCA line, headphone 6.3mm, optical/coax, RCA coax digital, HDMI eARC, variable RCA output/subwoofer out, Wi‑Fi (WiiM), Bluetooth 5.1 and a Cirrus Logic 24/192 DAC. The unit's streaming platform (WiiM/Pro‑ject Home), motorised analogue volume, multiroom capability and HDMI eARC push it into the 'fully featured' band for this class (score capped at the schema maximum).

Value for Money

80/100

Mixed signals in reviews: the Ear and Best of High End celebrate the marriage of analogue purity and modern streaming, but ecoustics explicitly calls the price 'steep' for ~40W per channel and warns you need high-sensitivity speakers. Given the feature set and sonic strengths, value is reasonable for buyers prioritising analogue fidelity and compact streaming, but the modest power means the price is harder to justify for those needing more drive.