>When a GG amp shows drifting output and grid current is this an
>indication of damaged cathode or grid? By this I mean drifting downward.
Gold-plated grids are susceptable to being coated with migrated
barium-oxide from the oxide cathode - IF the heater V is operated above
the max. rating. Apparently, as grid temperature increases, anode
current decreases. This condition has reportedly been a problem in some
Command 3CX800A7 amplifiers, as well as in the Dentron DTR-2000. The
problem can be avoided if one measures the cathode's heater potential..
Rich---
R. L. Measures, 805-386-3734, AG6K
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