The Pro-Ject Accu Box S2 sits at the top of Pro-Ject's S2 accessory range as a dedicated battery power supply designed to work with phono stages, DACs, headphone amplifiers, and other components in the S2 series. By replacing the standard mains adaptor with a rechargeable accumulator, the Accu Box S2 removes the primary source of electrical noise in a sensitive analogue system: the mains supply itself.
Battery Power and Sound Quality
The Accu Box S2 uses five cells of rechargeable Li-Ion batteries with a capacity of 2.5Ah. Because the supply is completely isolated from the mains during playback, it introduces no switching noise, ground loops, or mains-borne interference into the connected component. Pro-Ject describes the result as a more homogeneous and spacious sound, with improved separation and imaging compared to a standard switched-mode mains adaptor.
Outputs and Compatibility
The Accu Box S2 provides an 18V output on a 2.5mm DC connector for S2 series components, and a secondary 5V USB Type A output at 1A for DACs and other low-voltage accessories. The 21V charger input recharges the internal cells while the unit is not in use. It is compatible with a wide range of Pro-Ject products across the S2, DS2, E, and DS lines, including the Phono Box S2, Phono Box S2 Ultra, Stream Box S2 Ultra, Pre Box S2 Digital, Pre Box S2 Analogue, DAC Box S2, Head Box S2, Tube Box S2, and many others.
Construction
The casework is full aluminium and metal construction, matching the aesthetic of the rest of the S2 range. The front panel carries two LED indicators showing mains-connected status and charging status, along with a rotary on/off switch. The Accu Box S2 is available in black or silver to match Pro-Ject's component finishes.
