This is extremely impressive… IMO …
This fella makes his own valves, by all accounts he’s quite the artisan.
That way madness lies!
My father used to build tube amps (radios too) and the one he built for my grandfather way, way, way back in the day (1950’s I’d guess) to drive a huge mono speaker built into an even more massive enclosure was a beast. It was more like a PA system!