Recently a friend and I have been playing around with plate modulating GG Triodes in class C.? ?Just for fun.? ?My rig is a 450TH modulated by a pair of 100TH tubes.? His rig is a single 3-400Z modulated by a pair of 3-400Z tubes.? He is getting 600 watts carrier fully modulated.??
This is a tricky thing to get to work correctly but can be done. The trick was to place a choke and resistor in the grid line to self-modulate the grid. bingo. 100 percent modulated carrier.?
We noticed the 8877 3cx1500 actually has this mode listed on the PDF.? They specify grounded Grid Class C plate modulated, cathode driven configuration.??
It also states that you must modulate the Driver to 83 percent and plate modulate the rig to the rest required.? ?This is because the Drive power is never modulated.
Anyone ever try this?? I might try it for fun.? Probably wont use an 8877.?
I wonder what the purpose of this config was.? What was the advantage? They could get 1000 watts AM carrier fully modulated from a single 8877 in this config which is amazing. Maybe it never caught on?
I am simply going use my ranger to modulate the Cathode to 83 percent. Then tap off the ranger's modulators to drive the outboard modulates in phase through a transformer.? I will need to adjust the audio to the outboard modulators to get it working.??
C
