This compact headphone amplifier with three digital inputs was first introduced as far back as 2017. The basic design was created by John Westlake, who built a premium headphone amplifier around a D/A converter.
This way, you could utilise both digital audio sources and have an analogue output, so the Pre Box S2 could also be used as a preamplifier.
The internal of the compact Pro-Ject box has been revamped, including a new and more efficient power supply. The analogue output stage has been upgraded with higher Class A power, while the headphone output has been made more powerful. The circuitry around the ESS Sabre ESS9038 converter has been changed, including a redesigned master clock with a completely discrete circuit.
The analogue circuits are equipped with new polymer capacitors and MELF film transistors on a four-layer PCB with gold-plated tracks.
The DAC supports MQA via the USB input and Pro-Ject says it has managed to get the jitter noise down below 100 femtoseconds. That’s impressive for such a small box at 449 euros.
The Pre Box S2 Digital Edition 2023 can also be equipped with Pro-Ject’s Accu Box S2 power supply.
