The “Terrible Twins” – a push-pull amplifier with solid state pentodes

Inspired by Nelson Pass' work with Static Induction Transistors, and Lennart Jarlevang's  experience with the PASS-SIT-1 in a single-ended configuration, Alfred Hesener decided to see how ‘pentode' type solid state devices would fare in a push-pull arrangement. The article reviews design considerations and gives several tables comparing MOSFETs, BJTs and tubes on key performance figures. The article describes a complete design with performance data you can build. It uses just two devices in a push-pull arrangement, lots of iron and sounds quite good even without global feedback. Volume 4