Between 2007 and 2008 I built many tube audio amps and preamps. I studied the theory of tube in the books I could find.
After all the technology of tubes began to decline in the 1950s and today is no more taught in schools about this fabulous technology that existed for several decades until the advent of the transistor and integrated circuits. Morgan Jones’s books are quite recent, 2005 and is doing a good symbiosis of old and new. The Radiotron Designer’s Handbook is the edition of 1953, I bought an eBay auction and is in great condition. The other is 1947, Electronic Circuits and Tubes, I found in a second hand book store in SP.
I currently only posted the pictures of the main tube amps that I soon intend to provide the circuit diagrams.