Here’s a fascinating half hour long film about the history of the Mullard Blackburn factory and a quite detailed explanation of how tubes were manufactured there. The vast scale of the plant (6,200 workers) was remarkable. When one sees the array of specialized tooling and machinery required it’s easier to understand why modern tubes might lack the last bit of quality compared to those from the heyday of tube manufacturing.
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Thanks for posting this video. At one point we’re shown ECC82s coming off the production line. The ones in my preamp probably came from this very facility. I’ll appreciate them just a little more for having seen how they were made.
One example of many of how we’ve regressed, compared to previous generations, when it comes to producing quality products.
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During the heyday of the vacuum tube, the vacuum tube was only active device technology available for electronics in the consumer, industrial and military sectors. I’ve always believed the rigorous requirements for telecommunications that led to CCa tubes and JAN specifications for military applications drove quality and reliability in the industry as a whole. Today nobody uses small signal tubes in either industrial or military applications, so there isn’t the same incentive driving quality control that existed in the 50s and 60s. My two cents …
Wonder what happened to all the specialized equipment needed to produce top quality tubes?
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Even if it were to be found gathering dust in a warehouse someplace, the expertise to use it is gone. Unfortunately.
It’s not just so much the equipment…but the magterials utilized and the quality
of the metallurgy…the getters the thorium on the cathode the filament materials…
Best wishes
It’s unfortunate that these top quality tubes can no longer be produced. Now that I’ve discovered how much better the BHK 250 sounds with NOS tubes, not sure I can ever go back to using modern day tubes again. But with NOS getting more and more scarce and expensive to purchase, might have to move on from using tube gear, and hope solidstate gear continues to improve and eventually duplicates the magic of tubes.
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Don’t see myself needing to move on to all SS gear. But then that’s because when excellent NOS 6 and 12 volt tubes were available I swooped on them. I have a box of NOS glass that should keep me going into the foreseeable future. Those who more recently discovered NOS tubes from the height of high-quality production (mid 50s through the 60s) … different story. All the most desirable inventory from reputable vendors is sold.
It was hard for me a tube lover…to resign to the fact that quality
nos tubes are getting scarcer…few reproduction tubes have the same
life in hours as the nos tubes.
Even still have a tubed cd player.
Some reproduction tubes are ok - good…but not the same.
As a result I turned to ss amps pramps etc…unfortunately PS Audio
does not have an all ss Class A/AB amp in their lineup…so
Parasound with their very careful attention to the input section of
their JC5…The JC5 became my amp of choice…and cannot say
enough for it!
As the situation with China and Russia worsens will tubes become
unobtaniums? Hopefully not…
Best wishes everyone
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That would be me, and there lies the dilemma.
Can’t live without the magic these NOS tubes offer, but either unable to find the right vintage tubes I’m looking for, or scoffing at their asking price.
Blackburn is just up the road from me. probably explains why in the 80s i had that drawer full of mullard valves 
Some of it was purchased by foreign manufacturers. Matsushita in Japan is one such example.
While we’re reminiscing about valves from days of yore, here’s another one. A brief five minute look at the making of RCA tubes from roughly the same time period.