This is an interesting film on the production of Mullard Valves at the Blackburn plant.
www.techtubevalves.com/about_us/index.php
Click on vintage film reels
www.techtubevalves.com/about_us/index.php
Click on vintage film reels
Why are older tubes so much sought after
What is it with old stock tubes?? They were made years ago and surely by now we have must learned something about making them. So why are some people searching for old tubes. I have a Shanling CD player and I actually think the stock tubes are better than the 395a tubes.