Not something I expected to see in the 21st century! A miniaturised valve that looks a bit like an integrated circuit.
…operates as a complete triode tube, generating the same rich harmonics that are distinctive of conventional vacuum tubes
…less than 2% of power required by conventional vacuum tubes and making it easy to power the unit on batteries
In the field of lighting, governments are banning glass bulbs and hot filaments for energy efficiency reasons, while the audio world is going in the opposite direction.