Pro-Ject Head Box S3 Headphone Amplifier

A high-performance headphone amplifier built around a unique, fully balanced topology that redefines what is possible in its price class.

• Compact and stylish build
• Bypass RCA loop output for additional amplifier
• Solid metal casing protects from interferences

Built to Perform, Built to Last

Designed for audiophiles who demand power, precision, and flexibility, the Head Box S3 B supports both balanced and single-ended headphones and integrates seamlessly into modern desktop and hi-fi systems.

Its carefully engineered circuit design ensures a clean, dynamic, and highly controlled presentation, allowing headphones to truly perform at their full potential. By combining true balanced amplification with comprehensive connectivity and practical system integration, Head Box S3 B offers a compelling solution for listeners seeking reference-level performance in a compact and accessible format.

Fully Balanced Power

The Head Box S3 B features a fully balanced signal chain for both RCA and XLR inputs, ensuring maximum channel separation and minimal noise.

Its power stage features two TPA6120A2 amplifier chips, which deliver up to 820 mW of fully balanced output power.

On the unit itself, the balanced headphone connections are available via 4.4 mm Pentaconn and XLR outputs, while single-ended headphones are supported thanks to 3.5 mm and 6.3 mm outputs. A bypass RCA loop output allows easy connection to an additional amplifier or further system expansion.

Made in Europe

Build quality is a central design focus of the Head Box S3 B. The amplifier is housed in a premium, full aluminium enclosure that provides both mechanical stability and effective shielding. All control elements and buttons are crafted from high-quality aluminium, underscoring the product’s refined feel and durability.

Available in silver or black, the Head Box S3 B is made in Europe, reflecting a commitment to precise manufacturing, long-term reliability, and high engineering standards.

• Analogue Loop Output
  1 pair RCA
• Crosstalk
  < -81 dB
• RCA Input(s)
  1 Pair
• Balanced XLR Input(s)
  1 Pair
• Headphone Output
  3.5mm + 6.3mm + 4.4mm balanced + 4 Pin XLR balanced
• Headphone Amp Output Power
  480mW/8 Ohms, 680mW/16 Ohms, 820mW/32 Ohms, 320mW/300 Ohms
• Headphone Amp Signal-to-Noise Ratio
  >115 dB
• Headphone Output Impedance
  min 8 Ω
• Headphone Amp THD
  <0.002 %
• Headphone Amp Frequency Response
  < -0.25dB at 20Hz-20kHz
• Headphone Amp Gain
  15 / 9 (RCA / XLR) dB
• External Power Supply Rating
  18V-1A DC
• Dimensions (W x H x D)
  206 x 55 x 170 mm
• Weight
  0.95 kg