High End Features at an Affordable Price

The Phono Box S3 B is a phono preamplifier that offers a fully balanced design in a neat, small package. Pro-Ject have packed this tiny chassis to the brim with high-end features. One of those is their new True Balanced Connection. When used in combination with a Pro-Ject turntable with a 5-pin balanced output and 5P to XLR cable, you can achieve a totally balanced connection, minimising noise and delivering a breathtaking analogue signal.

Until now, balanced connections were exclusive to the RS range of products. The Phono Box S3 B brings those features to more affordable products.

Fully Discrete and Symmetrical Gain Stage

The new Phono Box S3 B gain stage uses a fully discrete layout. A discrete circuit is composed of disparate electronic components, and individual devices. The amplifier section is built of single parts and doesn‘t use any integrated circuits! That makes for an extended and more costly design process but results in the best sound quality. The fully symmetrical gain stage can optimise the signal-to-noise ratios, feeding the semi-passive, RIAA equalisation stage with a clean signal to work on.

True Balanced Connection

Part of the Phono Box S3 B's redesign is the inclusion of a balanced signal at a terrific price point. And the best part is that thanks to a range of new cables from Pro-Ject, these inputs can be used with any Pro-Ject turntable, whether it has RCA or 5P XLR outputs. 

However, to truly utilise the balanced circuitry, a Pro-Ject turntable with a moving coil cartridge and 5P output can be connected to the Phono Box S3 B with a 5P to XLR cable. The decreased noise and interference and improved dynamics have to be heard to be believed.

Full Technical Specifications

Input impedance10, 50, 100, 1k, 47k ohms

Gain (+ 6dB using XLR Out sockets)40, 45, 60, 65 dB

Signal / Noise ratio MC (60dB)85dBV, 90dBV - 'A' weighted

THD (20Hz-20kHz)<0,008% MM, < 0,01% MC

Subsonic filterat 20Hz with 18dB/octave

Line-level output1x pair RCA, 1x pair XLR

Power consumption18V/170mA DC, <0.5 W in standby

Weight930g without power supply

Input capacitance50, 150, 300, 400 pF

Signal / Noise ratio MM (40dB)103dBV, 110dBV - 'A' weighted

THD at 1 kHz<0,001% MM, < 0,005% MC

RIAA-equalization curve accuracy<0,3dB / 20Hz - 20kHz

Input1x 5-pin mini XLR / 1x pair RCA phono sockets

Power supply DC18V/500mA

Dimensions206 x 55 x 153 (164 with sockets) mm (W x H x D)