Pro-Ject Tube Box S3 B

The Pro-Ject Tube Box S3 B is a high-performance tube phono preamplifier designed to bring the warmth and musical richness of vacuum tube amplification to vinyl playback. Featuring a fully symmetrical and discrete gain stage, it combines traditional tube technology with advanced balanced circuit design for exceptional audio performance.

Equipped with two replaceable ECC83 (12AX7) vacuum tubes, the Tube Box S3 B supports both MM and MC cartridges, offering flexible cartridge loading and adjustable gain settings from 40dB to 65dB. Its 5-pin mini XLR balanced input and balanced XLR outputs enable True Balanced signal transmission, helping minimize unwanted noise and interference while preserving fine musical details.

With its dual mono architecture, semi-passive RIAA equalization and precision aluminium enclosure, the Tube Box S3 B delivers a refined analogue listening experience in a compact design. Available in Silver and Black finishes, it is an excellent choice for vinyl enthusiasts seeking the distinctive character of tube amplification with modern balanced connectivity.

Key Features

• Vacuum Tube Amplification:
  Features two replaceable ECC83 (12AX7) vacuum tubes, delivering the distinctive warmth and musical character of analogue tube amplification.
• True Balanced Circuit Design:
  A fully symmetrical and discrete gain stage processes balanced audio signals independently to minimize interference and preserve musical information.
• Balanced 5-Pin Mini XLR Input:
  Supports True Balanced connections from compatible turntables equipped with MC cartridges and dedicated 5-pin mini XLR phono cables.
• Balanced XLR Outputs:
  Provides balanced XLR outputs alongside conventional RCA outputs for flexible integration with a wide range of Hi-Fi systems.
• MM & MC Cartridge Compatibility:
  Supports both Moving Magnet (MM) and Moving Coil (MC) cartridges, offering versatile compatibility with different turntable configurations.
• Flexible Cartridge Loading:
  Adjustable input impedance and capacitance allow precise cartridge matching to optimize phono performance.
• Adjustable Gain Settings:
  Four selectable gain levels of 40, 45, 60 and 65dB provide flexibility for different cartridge output levels.
• Dual Mono Architecture:
  Separate amplification sections for the left and right channels help maintain channel separation and accurate stereo reproduction.
• Semi-Passive RIAA Equalization:
  A carefully designed RIAA equalization circuit ensures accurate frequency response during vinyl playback.
• Subsonic Filter:
  A selectable 20Hz subsonic filter with an 18dB/octave slope helps reduce unwanted low-frequency noise and turntable-induced rumble.
• Premium Aluminium Enclosure:
  The rigid steel and aluminium construction provides effective protection against external electromagnetic interference.

Feature Highlights

• Two replaceable ECC83 (12AX7) vacuum tubes for rich and natural analogue sound.
• Fully balanced and discrete gain stage with True Balanced connectivity.
• Compatible with both MM and MC phono cartridges.
• 5-pin mini XLR balanced input and stereo XLR outputs.
• Four selectable gain levels from 40dB to 65dB.
• Dual mono design with semi-passive RIAA equalization.
• Convenient front-panel adjustments for cartridge loading and gain settings.

Technical Specifications

• Tube Assembly:
  2 x ECC83 (12AX7)
• Cartridge Compatibility:
  MM / MC
• Input Impedance:
  10, 50, 100, 1k, 47k Ohms
• Input Capacitance:
  50, 150, 300, 400 pF
• Gain:
  40, 45, 60, 65 dB (+6dB using XLR outputs)
• Signal-to-Noise Ratio (MM, 40dB):
  97dBV / 105dBV (A-weighted)
• Signal-to-Noise Ratio (MC, 60dB):
  83dBV / 88dBV (A-weighted)
• Total Harmonic Distortion (THD) at 1kHz:
  Less than 0.005% (MM), less than 0.01% (MC)
• Total Harmonic Distortion (20Hz–20kHz):
  Less than 0.1% (MM), less than 0.03% (MC)
• RIAA Equalization Accuracy:
  Less than ±0.4dB (20Hz–20kHz)
• Subsonic Filter:
  20Hz / 18dB per octave
• Inputs:
  1 x 5-pin mini XLR balanced input
  1 x Stereo RCA Phono input
• Outputs:
  1 x Stereo RCA Line-level output
  1 x Stereo XLR Balanced output
• Power Supply:
  18V / 1000mA DC
• Power Consumption:
  18V / 800mA DC, less than 0.5W in standby
• Dimensions (W x H x D):
  206 x 81 x 153mm (164mm including connectors)
• Weight:
  1,010g (without power supply)
• Available Colours:
  Silver / Black
• Manufacturing:
  Made in Europe

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