Предусилители — Pro-Ject Pre Box S2 Analogue

The Pre Box S2 Analogue is a compact stereo line preamplifier from Pro-Ject Audio Systems. It switches between three analogue sources and sends the selected source to the amplification stage, with motorised volume control that can be operated from a remote. Finishes are black or silver, and the list price was EUR 249 including VAT. It belongs to the S2 generation of the company's Box Design range of compact electronics, all sharing the same narrow chassis width.

Key specs that matter

There are three line inputs - two RCA pairs and one 3.5 mm jack. The main RCA output is variable, while a second 3.5 mm output carries a fixed line level. Gain is 8.5 dB on the variable output and -2 dB on the fixed one. Input impedance is 15 kOhm. Frequency response runs from 20 Hz to 40 kHz within +0 to -0.5 dB, the noise floor is quoted at 100 dB A-weighted, and THD is 0.0005%. The chassis is 103 x 36 x 120 mm and weighs 405 g without the external supply.

Engineering and use context

Pro-Ject describes its circuit as advanced and built with high-grade components, aimed at a low noise floor. Connections are gold-plated. Pro-Ject makes the case from layered aluminium and metal, meant to protect against vibration and unwanted electromagnetic interference. Power is 5 V at 1 A DC from the included adapter, and the unit can also run from a 5 V power bank, which keeps mains supply noise out of the chain when required. Consumption is 100 mA, dropping below 1 W in standby. A 12 V trigger output lets the preamp turn on other products that have a trigger input, so a small system powers up from one control. Because the case is so narrow, it stacks neatly with its S2 siblings. The remote handles volume and input selection, so the preamp can stay out of reach while it is operated from a listening seat. The jack input on the rear accepts a portable player or phone without an adapter, and the fixed jack keeps its level regardless of the volume setting.

Pairing

The variable RCA pre-out can drive a separate stereo amplifier or powered monitors, while the fixed jack output can supply a constant-level signal to a recording device or another system. Three sources, for example a phono stage, a streamer and a portable player, can all be connected at once.

Alternatives

For owners who want digital inputs and a phono stage as well, Pro-Ject's Pre Box S3 is a larger preamplifier in the same Box Design range.