Jean Hirage promoted first here in europe the triode tube audio revival to the audio scene (specially the folks of Le Audiophile in france).
When doing this by presenting old style WE and other famous gears of the golden analog tube audio era in a small cinema in Paris, he used to learn his stuff from the japanese, which introduced him to their audio systems. Because the asians were clever and had an ear for the qualities of the US- audio gear from the 1920's on upwards, they purchased every WE system they could get a hold on and installed those big cinema systems at their small and tiny homes.
After learned and being educated about that sound, Hiraga went to europe again and made big marketing about those systems and their ideal of triode low wattage amps combined with big horn systems from the 1930s when audio in the US went towards become a commercial success.
Hiragas own circuits were heavily influenced by those audio designs, while what he designed himself being relative irrelevant, just for some freaks of the audio scene it became important.
So Hiraga's most importance lies in the fact that he introduced the european audiophiles with their own audio history, bringing the big names of european tube audio (and the US, of course) back into the game of what audiophile dreams are being created.
He himself must have made a fortune from his knowledge, achieved when such desirable things in europe went for the small money and some decades later brought the big cash to their owners. It was possible in the 1970s- 1980s to have a truck loaded with the garbage no other company any longer wants and usually had thrown into the bins for just a penny, making them run again and sell it for thousands of bucks to audiphiles.
And with those famous tubes it was the same. One can be sure that Le Audiophile and Hiraga had a stash of WE 300B tubes when they came up with their triode amp kits on the market, making a fortune selling it for a multiple they initially had to pay for the electron tubes.
Nelson Pass introduced himself to the audio community with his transistor gear, making it possible for the DIY to rebuild it by publishing its circuits in the scene. That was his way of guerilla marketing on those days to became a cult status in the audiophile scene.
The hidden quality treasures of those old gear and its noble sound lies in the art of manufacturing the parts and in the building style of the commercial pro stuff, which then in the later decades have been short cut by the penny pinchers of the controlling departments and have been made available for the ordinary audio consumer with the limited budget. Thats the way it was made for the big audio market which later have been taken over by the asians, making everything even more cheap in manufacture than the europeans and americans could ever do, due to their lower working salaries in the factories.
The fun story behind those known facts is, that the asians have sold their cheap style made audio systems to the foreign markets while being on treasury hunt for those old style tube audio systems around the world and buying everything in quantities, the older the better. Not telling the foreign audio scene and having themself an audio scene growing with old stuff which they hold hidden behind those language barriers that still exist today while the internet now has shown much of it even to the foreign world. They have grabbed everything good and sold their low quality audio mainstream stuff to the world instead.