Pro-Ject Head Box S3 B – Compact Fully Balanced Headphone Amplifier with XLR and 4,4 mm Pentaconn

Pro-Ject Audio Systems has built its reputation on compact, technically focused HiFi components designed to integrate seamlessly into real-world systems. With the Head Box S3 B, the company expands its BOX DESIGN portfolio with a fully balanced headphone amplifier aimed at today’s high-performance headphones. As headphones increasingly rival loudspeaker systems in resolution and dynamics, the demands on dedicated amplification continue to grow – especially in desktop and space-efficient HiFi environments.

Key Facts

• Fully balanced headphone amplifier in a compact aluminium chassis
• Balanced signal path for both RCA and XLR inputs
• Headphone outputs: 4,4 mm Pentaconn, 4-pin XLR, 6,3 mm stereo jack, 3,5 mm stereo mini jack
• Up to 820 mW balanced output power
• Amplifier stage based on two Texas Instruments TPA6120A2 chips
• RCA loop output for easy system expansion
• Solid aluminium enclosure and controls, manufactured in Europe
• Designed for clean signal handling and high channel separation

Fully Balanced Design for Clean Signal Handling

At the core of the Head Box S3 B is a consistently implemented fully balanced architecture. Both the RCA and XLR inputs feed a symmetrical signal chain, which is intended to provide high channel separation and a very low noise floor. In practical terms, this design approach is particularly beneficial when driving high-resolution headphones, where fine details and spatial cues can easily be compromised by noise or crosstalk.

Power Reserves for Contemporary Headphones

The amplifier stage relies on two TPA6120A2 chips from Texas Instruments, delivering up to 820 mW of balanced output power. This allows the Head Box S3 B to comfortably drive a wide range of modern dynamic and planar magnetic headphones. Rather than chasing extreme power figures, Pro-Ject focuses on controlled output and stable operation, aiming for a balance of authority, precision and long-term listening comfort.

Connectivity Tailored to Real Listening Habits

Flexibility is a key strength of the Head Box S3 B. Balanced headphones can be connected via either the 4,4 mm Pentaconn socket or the 4-pin XLR output, while conventional models are supported through 6,3 mm and 3,5 mm headphone jacks. On the input side, both RCA and XLR sources are accommodated, and a dedicated RCA loop output enables straightforward integration of additional components within an existing HiFi or desktop setup.

Build Quality and Manufacturing

In keeping with Pro-Ject’s design philosophy, the Head Box S3 B is housed in a solid, all-aluminium enclosure that provides mechanical stability and effective shielding against interference. The aluminium controls reinforce the impression of durability and precision. Manufacturing takes place in Europe, reflecting the company’s emphasis on consistent quality and sustainable production.

Price and Availability

The Pro-Ject Head Box S3 B will be available from authorised dealers starting January 2026. The recommended retail price is € 399,- including VAT.

Conclusion

With the Head Box S3 B, Pro-Ject Audio Systems delivers a compact headphone amplifier that prioritises fully balanced signal processing, practical connectivity and sensible power reserves. Its design avoids exaggerated specifications in favour of clean, controlled amplification suited to modern high-performance headphones. For listeners seeking a serious headphone solution that integrates effortlessly into HiFi or desktop systems, the Head Box S3 B represents a well-considered and accessible option in the advanced headphone amplifier segment.

Technical Specifications