It has been suggested to me that a 4-250 or 4-400 could be used in a grounded grid amp that is designed to use a 3-500Z. I wonder if anyone here has experience of doing this as I am in the process of acquiring a home brew amp that originally used 2 x 3-500Z.
I see the base and filament requirements are the same but can the grids all be strapped together and directly grounded?
What would be the bias requirements for ssb operation and cutoff in Rx to achieve by taking the filament CT above ground?
Mike.
Mike Fleetwood
Canberra Australia and Sidcup UK.
Worldwide email address is: mfleetwood@...
