PRO-JECT PHONO BOX S3 B – BALANCED AUDIOPHILE PHONO PREAMPLIFIER

The Phono Box S3 B is a fully balanced phono preamplifier developed for audiophiles who want maximum flexibility and uncompromising sound quality for both MM and MC cartridges. With a newly developed cabinet, front-mounted settings, and advanced discrete circuit design, the S3 B sets a new standard in its price class

HIGHLIGHTS

• 5-pin mini XLR input for balanced connection 
• Balanced XLR outputs as well as RCA line out
• Fully discrete and symmetrical gain stage without integrated circuits
• Semi-passive RIAA equalization for low noise and high precision
• Adjustable impedance and capacitance values (10–47k ohms / 50–400 pF)
• Gain range from 40 dB to 65 dB – ideal for both MM and MC cartridges
• Dual mono design for maximum separation and low distortion
• Subsonic filter at 20 Hz with an 18 dB/octave slope

BALANCED AND DISCRETE CIRCUITRY

The heart of the Phono Box S3 B is the fully discrete, symmetrical gain stage. By using individual electronic components instead of standard integrated circuits, it ensures more precise signal processing and significantly improved sound quality. The balanced design makes it possible to remove noise and interference effectively, so the music appears clean and detailed.

SEMI-PASSIVE RIAA AND SUBSONIC FILTER

After processing the balanced signals, they are routed through a semi-passive RIAA equalizer, which provides high precision and a natural frequency response. For vinyl enthusiasts with bass-related challenges, a built-in subsonic filter at 20 Hz reduces unwanted resonances without affecting the listening experience.

FLEXIBLE SETTINGS

The Phono Box S3 B lets you connect two turntables at the same time, with each input able to store its own settings. The front panel provides easy access to adjust impedance, capacitance, and gain directly, so the amplifier can quickly be adapted to different cartridges and systems. This makes it an exceptionally flexible solution for both experienced vinyl enthusiasts and those looking to upgrade from a simpler phono stage.

DESIGN AND CONSTRUCTION

With its new steel and aluminum chassis as well as a full aluminum front, the Phono Box S3 B offers a robust construction and effective shielding against interference. The compact cabinet measures 206 x 55 x 153 mm and weighs just 930 grams (without power supply), making it easy to integrate into any setup.