The compact headphone amplifier with three digital inputs was already launched in 2017. The basic design is credited to John Westlake, who built a premium headphone amplifier around a D/A converter. This allowed for the use of digital audio sources and provided an analog output, enabling the Pre Box S2 to also be used as a preamplifier.
The compact Pro-Ject box has been internally renewed, including a new and more efficient power supply. The analog output stage has been upgraded with higher Class A power, while the headphone output has become more powerful. The circuits around the ESS Sabre ESS9038 converter have been modified, including a redesigned master clock with a completely discrete circuit board.
The analog circuits are equipped with new polymer capacitors, MELF film transistors, on a four-layer circuit board with gold-plated traces.
The DAC supports MQA via the USB input, and Pro-Ject claims to have achieved jitter noise below 100 femtoseconds. This is impressive for such a small box priced at 449 euros.
The Pre Box S2 Digital Edition 2023 can also be equipped with Pro-Ject’s Accu Box S2 power supply.
