Предусилители — Pro-Ject Pre Box S2 Digital – Edition 23

The Pre Box S2 Digital - Edition 23, also called Edition 2023, is a revision of Pro-Ject's compact DAC and preamplifier with a headphone output. Pro-Ject lists a new headphone amplifier, a new analogue output stage, a redesigned discrete clock and a new internal power supply design for this edition, which is designed and handmade in Europe in black or silver at a list price of EUR 449 or GBP 399.

Key specs that matter

Two ESS9038Q2M 32-bit converters are used in a dual-mono concept. Over USB-B the unit handles PCM of up to 32 bit and 768 kHz and DSD512, with DSD1024 also indicated, whereas the S/PDIF coaxial and Toslink connections are limited to 24 bit and 192 kHz PCM. Outputs are a front 6.3 mm headphone socket and one variable RCA pair delivering 2.05 V. Headphone power is 6.6 mW into 600 ohms and 100 mW into 32 ohms, with 8 ohms as the minimum load. THD is 0.0003% at 0 dB, 2 V RMS and 1 kHz, dynamic range is 124 dBA, and the response covers 20 Hz to 20 kHz.

Engineering and use context

Pro-Ject states jitter below 100 femtoseconds for the reworked discrete clock. The analogue output stage is based on the SABRE9603Q and now runs with a higher Class A current. The unit takes 5 V at 1 A DC from the supplied adapter. It measures 103 x 37 x 122 mm and weighs 366 g without the supply, so it fits a desktop beside a computer or a shelf of other Box Design components. Inside, the circuit board is a gold-plated four-layer PCB populated with organic polymer capacitors and thin film resistors, and MQA decoding is done in hardware on the USB input. Besides seven filter characteristics there is one proprietary filter option.

Pairing

As a DAC, preamplifier and headphone amplifier in one, it combines three roles in a single box. The variable RCA output can drive active speakers directly or feed a separate power amplifier, making the unit the only control component needed between a computer or streamer and the amplification. A 2-year warranty covers the unit. Headphones from high-impedance studio models down to 8 ohm loads connect at the front, and the optical input accepts a TV or games console. The three digital inputs, USB, coaxial and optical, cover a computer, a streamer and a TV at the same time.

Alternatives

Pro-Ject's Pre Box RS2 Digital is the larger preamplifier and DAC positioned above the S2 Digital in the Box Design range.