Pro-Ject Phono Box S3 B

Balanced Phono Performance at the Entry Level

The Pro-Ject Phono Box S3 B is an entry-level phono preamplifier built around a fully balanced design in a compact steel and aluminium case. It brings Pro-Ject's True Balanced Connection, once reserved for the flagship RS range, to a far more accessible level. Two turntable inputs, front-panel cartridge loading and a fully discrete gain stage make it a flexible hub for a vinyl system.

Why You'll Love It

• True Balanced Connection. Paired with an MC cartridge and a balanced cable, the 5-pin mini XLR input opens a fully balanced signal path that filters out interference from household electronics, Wi-Fi and power cables.
• Two turntables, stored settings. Connect up to two decks at once, with all loading parameters for each input saved to memory, so switching between them needs no re-adjustment.
• Front-panel cartridge matching. Impedance and capacitance loading are set from the front of the unit, down to ultra-low values such as 10 ohms and 50 pF, to match a wide range of cartridges.

Under the Hood

• Fully discrete, symmetrical gain stage. The amplifier section is built from individual components with no integrated circuits, feeding a clean signal to the RIAA stage for a strong signal-to-noise ratio.
• Semi-passive RIAA equalisation. A semi-passive equalisation stage handles the RIAA curve accurately, quoted at under 0.3 dB across 20 Hz to 20 kHz.
• Rigid steel and aluminium case. The heavier casework adds rigidity and shields the sensitive circuitry from outside interference. Handmade in Europe.

CHT Insider Verdict

The Phono Box S3 B is aimed at listeners ready to move past a basic built-in phono stage. Balanced in and outputs, a discrete gain stage and dual-turntable support are unusual at this level, and the payoff is clearest with a moving coil cartridge on a balanced cable. Owners of RCA-only turntables still gain a well-built, quiet and adjustable phono stage with room to grow into balanced operation later.

Pro Tip: To hear what the balanced design offers, pair the S3 B with a moving coil cartridge and a Pro-Ject True Balanced cable into the 5-pin mini XLR input. A standard moving magnet cartridge over RCA uses only half of that signal path.