Pro-Ject Uni Box S3 Streaming Amplifier

The Pro-Ject Uni Box S3 is a compact all-in-one integrated streaming amplifier that reimagines the concept of a modern hi-fi system. Drawing upon the audiophile credentials of the MaiA S3, it introduces high-quality streaming without compromising core amplifier performance. Unlike many amplifiers that overemphasise digital integration at the expense of sound integrity, the Uni Box S3 offers a considered alternative. It elegantly balances both analogue and digital capabilities, preserving the musicality of traditional sources while offering cutting-edge streaming features.

Features

• Streaming by market leading technology WiiM OS ™
• App Pro-Ject Home
• Powerful Multi-Room capabilities
• Pro-Ject True Wireless Sending and Receiving:
  Stream any input to your network
• Countless streaming services
• Tidal Connect, Spotify Connect, Qobuz, etc...
• TV ARC input
• Wireless vinyl streaming from T2 W
• 2 x 40 watts @ 4 ohms
• Dual mono design principle
• 8 inputs (3x analog, 3x digital, 1x eARC, 1x WiFi/Bluetooth)
• Cirrus Logic CS4344 24bit/192kHz Multi-bit Delta Sigma
• S/PDIF inputs support up to 24bit and 192kHz
• Phono MM input
• Analogue volume control with motor driven potentiometer
• 6,3mm jack headphone output
• Variable output for subwoofer or second zone amp
• Remote control included
• Rigid aluminium casing protects against interference
• Available in silver or black
• Made in Europe

Done Right

Pro-Ject Audio Systems have stayed true to their analogue heritage with the Uni Box S3. Analogue sources—such as turntables—are never digitised, ensuring that their rich and natural sonic character remains intact. The preamplifier and power amplifier sections are entirely analogue, resulting in a sound that is both punchy and dynamically precise. Despite its sleek and compact aluminium casing, the amplifier delivers exceptional power and clarity. Importantly, the unit can be operated fully without the need for mobile apps or frequent software updates, ensuring reliability and simplicity over time.

Enhanced MaiA

Retaining all the analogue strengths of the MaiA S3, the Uni Box S3 includes the same powerful amplifier circuitry, a high-quality moving magnet (MM) phono stage with 46dB of gain, and both analogue and digital inputs. A dedicated headphone output adds further versatility. Enhancements in the Uni Box S3 include a carefully integrated streaming module, support for multi-room audio, and the ability to stream audio from connected analogue or digital devices—such as turntables, CD players or televisions—to other compatible network streamers in the home. A TV ARC input is also provided for seamless integration with modern televisions.

Powered by WiiM OS™

Thanks to a collaboration with WiiM, the Uni Box S3 features streaming capabilities driven by the robust and widely respected WiiM OS™. The Cirrus Logic CS4344 digital-to-analogue converter delivers high-resolution audio playback up to 24-bit / 192kHz. Streaming control is handled via the Pro-Ject Home app, which simplifies Wi-Fi setup and provides access to a wide range of both major and niche music streaming platforms. The app also enables users to build flexible multi-room audio systems using compatible Pro-Ject streamers. A long press of the front panel’s Stream button allows for a convenient Wi-Fi reset when needed.

Ins and Outs

The Uni Box S3 is equipped with a broad range of input and output options, including a dedicated MM phono RCA input and two line-level RCA inputs for devices such as the CD Box S3. Digital sources can be connected via coaxial or optical S/PDIF inputs, utilising the onboard DAC for high-resolution playback. On the output side, users can connect loudspeakers using 4mm banana plugs, or enjoy private listening via the front headphone jack. A variable RCA output allows integration with a subwoofer or an additional power amplifier, offering users exceptional flexibility in configuring their audio setup.

Specifications