Amplifier for headphones of the Austrian company Pro-Ject.
Head Box S is designed to connect one pair of headphones. On the front panel - output, volume control, on the back - input and output (RCA), the last - non-adjustable, for recording on a tape recorder or external amplifier. There is also a power connector, since the power supply unit in the Head Box S is external - a standard network adapter is inserted into the outlet. Solid metal body and aluminum front panel.
High-class components are used in the chains, which are reliably protected from vibrations and electromagnetic interference. The model is produced in Austria.

Specifications
Reproduced frequency range: 10 – 120000 Hz (-1 dB)
Harmonics coefficient: 0.003%
The signal/noise ratio is 95 dB
Inputs linear x1
Headphone outputs: x1, linear x1
6.3 mm headphone jack
External power supply unit
Dimensions (WxHxD) 103x36x104 mm
Weight: 0.6 kg
Output power: -330 mW / 30 Ohms, -60 mW / 300 Ohms