All the proponents of grounded grid are violating Rich's Rules - that the
voltage on the screen grid of a pentode must have constant voltage to
produce an acceptable signal.
Yet, in a grounded grid amplifier, the screen grid voltage varies with
drive - just as the control grid voltage varies. It is not zero volts
simply because the screen voltage is grounded. Heavy grid and screen
current flow - contrary to Rich's Rules.
And, in grounded grid, the tetrode or pentode tube is being used in a manner
other than how the factory intended.
Lastly, many commercial sweep tube amplifiers put out a -22 db distortion
figure on a good day, if operated according to the factory.
Using the same reasoning as Rich, may I proclaim that all grounded grid
ampllifiers which use tetrodes are bad since I have measured a -20 db
distortion level of a commercial grounded grid amplifier?
Colin K7FM
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