[Amps] Question #2: 4-125A linear amplifier

[Robert Groh]

OK here I am really going to tempt the gods with a strange idea of a 'classic' 
medium power amplifier using one or two of my 4-125A tubes - HF, window in the 
front so I can watch the tube plate(s) glow, driven by a CE 20A exciter.  Maybe 
just a couple of bands, maybe one band. Couple of ideas already in hand from 
past issues of QST (I haven't had a chance to prowl through the old Handbooks).  


So again I'm here with hat in hand - soliciting all thoughts on the idea (I 
already know there are many better tube choices today as well as solid state 
amplifiers but let's stick with the 4-125As).  Pointers to reference articles, 
ideas, things not to do (again excluding the idea of NOT using a 4-125A!), etc.

I would definitely provide warmup delay, adjustable (and monitored) filament 
voltage, cool down delay. Other protection?  Really thinking about using it as a 
grid driven tetrode amplifier. 


73
Bob, WA2CKY