Pro-Ject Phono Box S3 B


Phono Preamplifier with Balanced Connections

The Phono Box S3 B is a proficient phono preamplifier that offers a fully balanced design in a neat, small package.

This tiny chassis is packed to the brim with high-end features. One of those is the new True Balanced Connection. At Pro-Ject, balanced connections were previously exclusive to the RS range of products until now. The Phono Box S3 B brings those features to a remarkably accessible price point.


Pro-Ject Phono Box S3 B

High End Features Made Accessible

The Pro-Ject Phono Box S3 B comes in completely redesigned casework. The larger size (than the S2) enables a completely new feature set that breaks new ground at the price. The steel & aluminium case offers very high rigidity and isolation against outside interferences, which is essential for the new technology inside.

Fully Discrete and Symmetrical Gain Stage

The new Pro-Ject Phono Box S3 B gain stage uses a fully discrete layout. A discrete circuit is composed of disparate electronic components and individual devices that result in better sound quality.

The amplifier section of the Pro-Ject Phono Box S3 B is built of single parts and doesn‘t use any integrated circuits. This makes for a longer and more costly design process but the resulting audio speaks for itself.

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.

SKU: Phono Box S3 B Categories: ,
Weight 930 g
Dimensions 153 × 206 × 55 mm


Black, Silver

Input impedance: 10, 50, 100, 1k, 47k ohms
Input capacitance: 50, 150, 300, 400 pF
Gain (+ 6dB using XLR Out sockets): 40, 45, 60, 65 dB
Signal / Noise ratio MM (40dB): 103dBV, 110dBV – ‘A’ weighted
Signal / Noise ratio MC (60dB): 85dBV, 90dBV – ‘A’ weighted
THD at 1 kHz: <0.001% MM, < 0.005% MC
THD (20Hz-20kHz): <0.008% MM, < 0.01% MC
RIAA-equalization curve accuracy: <0.3dB / 20Hz – 20kHz
Subsonic filter: at 20Hz with 18dB/octave
Input: 1x 5-pin mini XLR / 1x pair RCA phono sockets
Line-level output: 1x pair RCA, 1x pair XLR
Power supply DC: 18V/500mA
Power consumption: 18V/170mA DC, <0.5 W in standby
Dimensions: 206 x 55 x 153 (164 with sockets) mm (W x H x D)
Weight: 930g without power supply


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