The Pro-Ject Amp Box S3 is a dedicated stereo power amplifier designed to partner a preamplifier or streamer with a built-in preamp stage, such as the Pro-Ject Pre Box S2 Digital. Sitting in the compact S3 Box Series, it delivers audiophile-grade amplification in a format that takes up minimal shelf space, making it an ideal partner for desktop or secondary-room systems.
Refined Topology
At the heart of the Amp Box S3 is a revised PCB layout with a more sophisticated circuit topology than its predecessor. The redesign reduces total harmonic distortion and improves the signal-to-noise ratio, bringing measurably cleaner signal amplification without sacrificing character. Pro-Ject have deliberately tuned the sound to share the warm, musical quality associated with valve amplification, offering a listening experience that feels engaging and natural rather than clinical.
Compact and Versatile
At just 103mm wide, the Amp Box S3 fits easily on a desk, a shelf, or alongside other components in a compact hi-fi stack. It suits a broad range of applications: as the power stage in a high-quality desktop system, as an amplifier for a secondary or multiroom zone, or as an upgrade to the amplification section in a home cinema surround setup. The ultra-compact metal casing is robust and designed in Europe to match the aesthetic of other S3 Box Series components.
Connectivity
Input is via a single pair of RCA sockets, with a 25k ohm input impedance suitable for all standard preamplifier outputs. Speaker terminals accept 4mm banana plugs, spades, pins, or bare wire for maximum flexibility. A 12V DC trigger input and output (2.5mm jack) allow integration with systems that support automated power sequencing. Power comes from an included universal switch-mode supply (20V/3A DC, 100 to 240V), so the amplifier travels and operates worldwide without modification.
