[Amps] Alpha 77Dx -Adding Grounded Grid Filament Choke

[TexasRF@aol.com]

A secondary issue on the filament transformer grounding/ungrounding:
 
When the transformer secondary is floating, it then becomes important that  
the transformer primary to secondary breakdown voltage is greater than the 
plate  voltage in case of a plate to ground arc/flashover (remember the grid  is 
grounded). If the grid meter circuit blows open, the full plate voltage  can 
appear on the cathode/filament circuit.
 
A couple of really robust back to back diodes can protect the grid meter  but 
they have to be there to do it. Also, does anyone have info on how quickly  
large diodes will conduct in a flashover scenario? Seems that the rise time  
could be a problem but I am not sure about that.
 
73,
Gerald K5GW