Pro-Ject Uni Box S3 Integrated Streaming Amplifier

Pro-Ject Uni Box S3 Integrated Streaming Amplifier

The Pro-Ject Uni Box S3 combines stereo amplification, WiiM-powered network streaming, a moving-magnet phono stage and TV audio connectivity in a compact aluminium component, making it a practical centrepiece for a two-channel hi-fi system.

There are eight selectable inputs covering a turntable, conventional analogue sources, digital components, TV audio and network streaming. Its analogue preamplifier and power amplifier path keeps connected analogue sources in the analogue domain, while a separate Cirrus Logic DAC handles digital playback. That distinction is useful for someone with an existing turntable or CD player who also wants modern streaming without adding several components.

WiiM-Powered Streaming

Modern music access with familiar component controls

WiiM OS provides the network streaming platform, while the Pro-Ject Home app handles streaming setup and control. The digital section uses a Cirrus Logic CS4344 converter supporting up to 24-bit/192kHz audio. Spotify Connect, TIDAL Connect and Qobuz connectivity bring popular music services into the same system as your physical sources.

Connect the Uni Box S3 to a suitable home Wi-Fi network and use the app for streaming functions. Traditional source selection and volume remain available directly on the front panel, so ordinary amplifier use does not depend on keeping a phone nearby.

Analogue Amplification and Speaker Matching

Compact power for an appropriately matched pair of passive speakers

The Uni Box S3 is rated at 2 x 23W into 8 ohms or 2 x 40W into 4 ohms, measured at 1% THD. That is substantial capability for its compact dimensions, although room size, listening distance and speaker sensitivity remain important when choosing a matching pair.

It is well suited to a modest living-room or study system with efficient standmount speakers. For a large room, long listening distance or consistently high playback levels, we would check speaker requirements carefully before recommending this amplifier.

Turntable and Analogue Sources

A dedicated MM phono input and two additional RCA inputs

The built-in moving-magnet phono stage allows a compatible turntable to connect directly, without requiring a separate phono preamplifier. Two further stereo RCA inputs accommodate components such as a CD player, external DAC or another line-level source.

Turntables with their own built-in phono stage should normally feed a line input, rather than sending a preamplified signal into the Uni Box S3's phono input. Check the cartridge type and phono-stage arrangement before making the connection.

TV and Digital Audio Integration

Bring television and digital sources into a stereo system

HDMI ARC provides a convenient path for compatible TV audio, alongside two Toslink optical inputs and one coaxial S/PDIF input for other digital components. The compact unit can therefore serve as the amplifier for both everyday music listening and TV sound through a pair of passive hi-fi speakers.

Check the television's ARC output settings and supported audio format during setup. This is a stereo amplifier rather than a surround-sound AV receiver, so it should be selected for two-channel use.

Headphone Listening and System Expansion

Private listening and a variable line-level output

A front headphone socket is backed by a dedicated output rated at 70mW into 32 ohms. A variable stereo RCA output also provides a connection to compatible downstream equipment, allowing flexibility when planning an expanded system.

Placement and Daily Use

Small enough for a shelf, with sensible ventilation still required

The aluminium enclosure is 206mm wide and 55mm high, with a chassis depth of 153mm or 176mm including sockets. Leave room for cable bends, access to the rear terminals and airflow around the case. For wireless streaming, consider router distance and local network reliability when choosing the final shelf position.

Available Variants

• Black: black aluminium finish
• Silver: silver aluminium finish

Key Features

• Integrated two-channel amplifier with WiiM-powered streaming
• 2 x 23W into 8 ohms or 2 x 40W into 4 ohms at 1% THD
• Dedicated moving-magnet phono input and two stereo RCA line inputs
• HDMI ARC, two optical and one coaxial digital input
• Cirrus Logic CS4344 DAC supporting up to 24-bit/192kHz
• Wi-Fi and Bluetooth wireless connectivity
• Headphone output and variable stereo RCA output
• Compact aluminium chassis in Black or Silver

Specifications

Detailed Technical Specifications

For those who like to drag out all the useful bits

Important Notes

• This amplifier drives passive stereo speakers; speakers are not part of the amplifier itself.
• Use the MM phono input only with a compatible cartridge-level turntable signal. Turntables with active internal phono stages should normally use a line input.
• HDMI ARC is for compatible TV audio connections; this is not a multichannel home theatre receiver.
• Ensure adequate ventilation and rear clearance for speaker cables, HDMI and power connections.
• Contact The Audio Experts for current stock, finish availability and speaker-matching advice.

The Audio Experts Take

The Uni Box S3 is appealing for a compact two-channel system where the owner wants to play records, stream music and improve TV audio without filling a shelf with separate components. Its proper MM phono input and analogue signal path are useful distinctions from many streaming-first amplifiers.

The main decision is speaker matching. With 23W per channel into 8 ohms, we would pair it thoughtfully with speakers and a listening distance that suit its output, rather than judge it by the amplifier's small size. For a study, apartment or carefully planned living-room stereo, it brings together a well-rounded connection set and accessible everyday control.