PrimaLuna EVO 300 Tube Hybrid Integrated AmplifierTube in the Front, Solid State in the Back The input stages of the EVO 300 Hybrid use two 12AU7 tubes in the gain stages, and four 12AU7 driver tubes. The doubled driver tubes ensure a lower impedance on the output stages, allowing for large dynamics, a huge soundstage, and lots of beautiful harmonics and texture. The solid state output stages use cascading JFETs from Linear Systems and each channel boasts two complementary pairs of MOSFETs from