On Sunday, June 2, 2019 at 7:48:36 PM UTC-4, Cursitor Doom wrote:
I didn't know people still do this...
Yes, they do...the fellow here is extremely talented...even produced curves for his tubes.
I lived not very far from the Sylvania tube factory in Pennsylvania. Quite a few articles on the net about it and the physics and metallurgy that went into designing and fabricating high quality electron tubes. It was generally acknowledged that Sylvania tubes equaled or surpassed RCA tubes in quality and long-life.
In a wild day dream one week I did quite a bit of searching of what it would take to create a high quality tube factory equal to what sylvania had. To actually put the equipment in place and the associated know how. It seemed to me that a lot of the 'art' (craftsmanship) has been lost and would need to be relearned, thus making a business endeavor extremely risky. It also seemed that some of the underlying physics/chemistry/metallurgy would have to be rediscovered. That put it out of my scope of knowledge.
I can see an ad in IEEE spectrum: Wanted - electronics engineer/physicist experienced in electronic vacuum tube design and fabrication. Don't think I'd get many takers.
Looks like will have to subsist on Russian and Chinese 'knock-offs'...
Well, it was a nice dream...
** In the late 1970s when the Sylvania tube factory closed, the manufacturing equipment was offered at auction and the purchaser was Hartley Peavey of the Peavey Electronics Corporation - maker of thousands of tube guitar amps.
His idea was to manufacture runs of tubes commonly used in audio amplifiers and sell them under his brand to other amp makers and the public.
Then the Soviet Union collapsed, as predicted by Ronald Reagan, making Russian
tubes available to the rest of the world at prices lower than the cost of production in the USA. Many of these were near identical to popular RCA and GE types or were easily enough adapted to match them in term of pin out etc.
The Chinese had already bought up machinery from Europe and were making similar tubes of very ordinary quality at low prices too.
the Sylvania machinery is sitting in storage somewhere in the US.
The Russians had always been making tubes of good quality for home and military consumption so the engineering knowledge was in place while the Chinese OTOH had a bit of learning to do.