I came across this video, by accident on Youtube of French radio amateur, Claude Paillard ( Callsign F2F0) who makes his own valves by hand in the traditional way. It gives you an idea of what it takes to make your valves. He is making a triode so if you do this twice and put in one glass tube you have an ECC81 / ECC83/ ECC99.
The video is made in France so the few captions that are in the 17 minute video are in French and there is no commentary so there is no language problem. It really lets you see that the key skill in making valves is glass blowing. It is more like creating a work of art than an electronic component . Volume production will follow similar steps but of course a lot more automation used. Click here for the link to the video
Want to see how valves ( tubes ) are made?
