PRO-JECT TUBE BOX S3 B

Pro-Ject Tube Box S3 B – Balanced Tube Phono Preamplifier for MM & MC Cartridges

The Pro-Ject Tube Box S3 B is a high-end tube phono preamplifier designed for audiophiles who demand exceptional analog performance from their vinyl playback system. Combining the musical warmth of vacuum tubes with a fully balanced discrete circuit design, the Tube Box S3 B delivers outstanding sound quality, precision and flexibility.

Equipped with two ECC83 (12AX7) vacuum tubes, this phono stage provides a rich, dynamic and natural sound signature, revealing the finest details of your vinyl records. The fully balanced dual-mono architecture minimizes noise and improves channel separation, resulting in a wider and more precise soundstage.

The Tube Box S3 B supports both MM (Moving Magnet) and MC (Moving Coil) cartridges and offers a wide range of adjustable settings for gain, input impedance and capacitance. These controls allow precise matching with virtually any cartridge, ensuring optimal performance in any hi-fi system.

For maximum system flexibility, the unit features both balanced and unbalanced connections, including RCA inputs, a mini-XLR balanced input and both RCA and XLR outputs. Built into a robust metal chassis with excellent shielding, the Tube Box S3 B is a perfect upgrade for serious vinyl enthusiasts seeking audiophile-grade phono amplification.

Key Features

• High-end tube phono preamplifier
• Compatible with MM and MC cartridges
• 2 × ECC83 (12AX7) vacuum tubes
• Fully balanced dual-mono circuit design
• High-performance discrete gain stage
• Balanced mini-XLR input and RCA phono input
• Balanced XLR and unbalanced RCA outputs
• Adjustable gain, impedance and capacitance
• High-precision semi-passive RIAA equalization
• Integrated subsonic filter
• Shielded metal enclosure for reduced interference
• Compact design from the Pro-Ject Box Design S3 series

Audiophile Analog Performance

The Pro-Ject Tube Box S3 B features a sophisticated discrete circuit design that avoids integrated operational amplifiers, ensuring a more natural and transparent sound reproduction. The balanced signal path significantly improves the signal-to-noise ratio and reduces interference, delivering cleaner and more dynamic playback.

The semi-passive RIAA equalization network guarantees highly accurate vinyl playback while the extensive adjustment options allow the phono stage to be perfectly matched with a wide range of cartridges and turntables.

Technical Specifications

• Product type: Tube phono preamplifier MM / MC
• Tubes: 2 × ECC83 (12AX7)
• Gain: 40 / 45 / 60 / 65 dB
• Input impedance: 10 Ω, 50 Ω, 100 Ω, 1 kΩ, 47 kΩ
• Input capacitance: 50, 150, 300, 400 pF
• Signal-to-noise ratio: up to 103 dB (MM)
• Total harmonic distortion: <0.001% (MM) / <0.005% (MC)
• RIAA accuracy: <0.3 dB (20 Hz – 20 kHz)
• Subsonic filter: 20 Hz, 18 dB/octave
• Inputs: 1 × RCA phono, 1 × balanced mini-XLR
• Outputs: 1 × RCA, 1 × balanced XLR
• Power supply: 18 V DC
• Power consumption: approx. 800 mA DC
• Dimensions (W × H × D): 206 × 81 × 153 mm
• Weight: approx. 1 kg

Why Choose the Pro-Ject Tube Box S3 B

• Warm and musical sound thanks to vacuum tube amplification
• Balanced connections for high-end hi-fi systems
• Wide compatibility with MM and MC cartridges
• Highly adjustable settings for optimal system matching
• Compact audiophile construction with premium components

The Pro-Ject Tube Box S3 B is the ideal phono stage for vinyl enthusiasts looking to elevate their analog system with the refined sound of tube amplification and the precision of modern balanced circuitry.