You are following my steps
- the 833 is part of my dreams and nightmares ...
Dreams because with this tube we can have a single tube really powerful amplifier. However it has two immediate problems - 10Vx10Amp = 100W filament - just for the filament , it will heat a lot. Also sometimes in order to get high power the 833 is operated at up to 1800V. IMHO anything over 1200V can be problematic. You need special insulation materials and components, and in case of service, only very specialized people are able to handle it.