Great post, Damir, both here and on the Group Build forum! An example of output Z and damping factor calculated using these equations:A strapped-triode EL34 operating at 90mA Ia, using a "typical" 3K reflected impedance OPT will have an output Z of about 2.1 ohms and a damping factor of about 3.7. As mentioned in the Group Build post, there are lots of variables to consider. YMMV.
Thermionic