Thanks Damir; it's a lot to digest but I am working on it, It's hard to follow some of the math because of the computor only lets you use certain symbols and I have to adapt to those. I will have more questions as I get the concepts. My goal is to design a simple PP amp all by my lonesome using 6w6 output tubes and 12ax7 driver and 6sn7 phase splitter. Only because I have those tubes and some transformers on hand. How is your 300B coming along?