https://korgnutube.com/en/ By itself, you could create a small tube preamp that could be used to create a tube mic sound especially on direct inject app's. It compact size and low power requirements are crazy cool! Headphone amp would be another very practical use. Ultimately you could use it before a well-designed transistor amp to reproduce the sound of a single end high power tube amp. As I understand it microphonics is still an issue so maybe base station use first. You can fit 5 or 6 of these in one mans hand. The power and current is so much lower than what is needed for a 12AX7.