Steve Lafferty has released the details of a new laboratory instrument that he designed and developed for vacuum tube analysis. It takes the meaning of “tube testing” to a new level. While extremely accurate, it is also highly complex, and therefore probably beyond the capabilities of most hobbyists to build at home.
Nevertheless, the design process shown in the article makes for quite a fascinating “read”!
http://www.tronola.com/html/vacuum_tube_analyzer_page1.html