The problem is the term feedback
being applied to this circuit
because the output is not being
fed back to the input.
The grid is the input and the
tube's output is not influencing
the input just the tube's operation.
The input IS the grid to ground signal
and that is not being changed by the
cathodes signal at all.
The word "back" in feedback means that it must be
fed back to a previous point which is not happening.
DanL
