Tube Box S2

About the Tube Box S2

The Pro-Ject Tube Box S2 is a high-end phono preamplifier designed for both MM and MC cartridges. It features a fully discrete circuit design without any operational amplifiers (OpAmps) and includes two replaceable ECC83 tubes (12AX7A) for tube rolling and sound shaping, allowing users to customize the sound signature. The preamp offers precise RIAA equalization in two parts (passive and active), ultra-low noise circuitry with an FET input stage, and dual mono circuitry for optimized channel separation. It has multiple gain settings (40, 43, 50, 53, 60, and 63 dB) selectable on the front panel, and five variable input impedance settings (10Ω, 100Ω, 470Ω, 1kΩ, 2kΩ) for low-output MC cartridges, plus a fixed 47kΩ input impedance for MM and high-output MC cartridges. Input capacitance can be adjusted (47pF to 587pF) via dip switches. The unit includes a front-panel subsonic filter button (18 dB/octave roll-off at 20 Hz) to reduce low-frequency rumble. The chassis is made of a sandwich aluminum/metal casing that protects against vibrations and electromagnetic interference, available in black or silver finishes. It uses gold-plated RCA inputs and outputs and is powered by an external 18V/1A DC power supply. Dimensions are approximately 103 x 73 x 131 mm, and it weighs 410 g without the power supply. The Tube Box S2 delivers a full, relaxed, and laid-back sound with lush mids, comparable to much larger high-end tube phono preamplifiers. It is handmade in Europe and represents a compact, high-end solution for vinyl playback.