The Tube Box S2 is the very first Pro-Ject product to feature a fully discrete circuit design that eschews the use of any OpAmps. It's also is the first product to come with replaceable tubes for tube rolling and sound-shaping. This offers an array of options to choose from and lets you alter the sound signature to your preference. Tube Box S2 offers a full, relaxed, laid back sound with lush mids, just like you would expect from any high quality tube phono pre-amplifier. It offers support for both MM and MC cartridges and comes with many gain settings that are adjustable on the front panel. Five variable input impedance settings are available to adjust to any MM cartridge, the 47k ohms input impedance setting is fixed and suited for high output MC cartridges. The aluminium/metal casing protects against vibrations and electromagnetic interference to ensure the best possible sound.