On Jun 25, 2006, at 1:17 PM, Tom W8JI wrote:
> The most difficult to stabilize tubes are generally those
> with the longest and thinnest element leads. The 811/572
> family falls into this category.
> If you look at older amps like the Heath Warrior and Gonset
> (?not sure of number?) 811 amps they neutralized the PA by a
> third winding in the filament choke.
After producing the Warrior and the GSB-201, finding that even though
the RCA Tube Manual's "neutralization" circuit deceased feedback at
HF, due to phase shifting as freq shifted, they came to realize that
it had the opposite effect at VHF, and neither Heath nor Gonset
produced another "neutralized" g-g amp.
R L MEASURES, AG6K. 805-386-3734
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