As I've been sorting through my 8877 filamant issue, I have noted that some
GG 8877 designs tie the filamant and cathode together while other designs do
not. The designs that keep the cathode isolated from the filament generally
do not use a filament choke since what little RF that may be coupled to the
filament can be easily bypassed to ground through judiciously placed bypass
caps. In these designs, I have seen one side of the filament grounded and
alternatively, designs where the filament is balanced and floating above
ground with each side of the filament connected directly to the secondary of
the filament transfomer.
Given these design variances, is there a consenus of a preferred method? Is
there a measured performance deficiency in the designt that grounds one side
of the 8877 filament? I apologize if this has been addressed in the past.
I searched the archive titles, but found nothing directly on-point with this
subject. Thanks.
-Paul, W9AC
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