Pro-Ject Head Box S3 B Headphone Amplifier

With the Head Box S3 B, Pro-Ject Audio Systems presents a particularly compact headphone amplifier that offers an entry into true balanced technology. Despite its small dimensions, the device features a fully balanced signal architecture, four headphone outputs, and sufficient power reserves for a wide range of modern headphones.

The Head Box S3 B is aimed at music lovers who want to take their headphone system to a new level – with clear, controlled playback and audiophile technology in a compact format.

Fully symmetrical amplifier architecture

The heart of the Head Box S3 B is a fully symmetrical amplifier topology. This design ensures particularly low-noise signal processing, improves channel separation, and reduces noise and distortion to a minimum.

Even the input stage operates fully symmetrically – via both RCA and XLR connections. This ensures that the audio signal is optimally processed right from the start and can fully develop its sonic potential.

Especially in symmetrical operation, the amplifier impresses with an exceptionally high signal-to-noise ratio and an impressively precise spatial representation.

High-performance output stage

For amplification, Pro-Ject relies on a power stage with two high-quality TPA6120A2 amplifier chips. These components are known for their high bandwidth, excellent dynamics, and extremely low distortion.

The Head Box S3 B delivers up to 770 mW of output power into 32 ohms in unbalanced operation. This provides ample power reserves to drive most dynamic and planar magnetic headphones with ease.

The playback remains clean, controlled and free of audible artifacts at all times – even at higher volumes.

Four headphone outputs for maximum flexibility

A special feature of the Head Box S3 B is its extensive range of connections on the front panel. A total of four different headphone outputs are available:

• 6.3 mm jack (unbalanced)
• 3.5 mm jack (unbalanced)
• 4.4 mm Pentaconn (symmetrical)
• 4-pin XLR (balanced)

This selection allows you to connect virtually any modern headphones without an adapter. Furthermore, two headphones can be used simultaneously – ideal for listening to music together or for directly comparing different headphone models.

Flexible integration into existing systems

On the rear panel, the Head Box S3 B offers both a classic RCA input and a balanced XLR input. Selection is conveniently made via a switch on the front panel.

Additionally, a RCA bypass output is available. This allows the input signal to be routed directly to an integrated amplifier or other component. This makes it easy to integrate the headphone amplifier into existing hi-fi systems.

High-quality workmanship

Like all devices in the S3 series, the Head Box S3 B also impresses with its housing made entirely of aluminum. This reliably protects the sensitive electronics from external interference and contributes to mechanical stability.

The controls and buttons are also made of solid aluminum and convey a high-quality, durable feel.

The Head Box S3 B is available in two elegant finishes: silver or black.

Highlights at a glance

• Fully symmetrical headphone amplifier topology
• Powerstage with two TPA6120A2 chips
• Up to 770 mW output power at 32 ohms
• Symmetrical signal processing for RCA and XLR inputs
• Balanced headphone outputs: 4.4 mm Pentaconn and 4-pin XLR
• Asymmetrical outputs: 3.5 mm and 6.3 mm
• Four headphone jacks on the front.
• RCA bypass output for integration into hi-fi systems
• High-quality, all-aluminum housing
• Aluminum controls
• Available in black or silver
• Designed and manufactured in Europe

TECHNICAL DATA

• Output power: 670 mW/16 ohms, 770 mW/32 ohms, 300 mW/300 ohms
• Headphone output: 3.5 mm, 6.3 mm, 4.4 mm balanced, 4-pole balanced XLR
• SNR: > 115 dB “A”-weighted at 1 kHz
• THD: < 0.002% at 1 kHz @ 500 mV input
• Crosstalk: < -81 dB at 10 kHz
• Gain: 15 dB / 9 dB (RCA input / XLR input)
• Frequency response: < -0.25 dB at 20 Hz–20 kHz
• Analog inputs: 1 pair RCA/Cinch, 1 pair XLR
• Analog loop outputs: 1 pair of RCA
• Headphone impedance: min. 8 ohms
• Power supply: 18 V/1 A DC, 110–240 V, 50/60 Hz
• Standby power consumption: < 0.5 W
• Dimensions W x H x D: 206 x 55 x 153 (170) mm
• Weight: 950 g without power supply