On Feb 5, 2005, at 4:51 AM, George KB2Z wrote:
Good morning all,
I'm new to the list and had a couple of questions that have been
bothering me for awhile.
This one is a bit off, but would anyone have an answer to why 2x3-500
amplifiers in gg configuration sometimes have 1,2, or 3 caps
paralleled to the grids, some have a choke paralleled to the caps,
some are tied directly to ground?
I have seen schematics of same series amps done with the caps and
coils and without. As an aside it looks like Japanese versions of some
of the same amps have the grids tied directly to ground. ( HL-2k) Is
it a spectral purity FCC thing?
No, because a 3-500Z is quite linear up to c. 420mA of anode-I without
any kind of RF-N feedback. . In fact, transceivers are not even close
on IMD to a 500Z.
As an aside, The Japanese HL-2k schematic shows a choke in the
filament return and the US version does not. I'm guessing the choke is
for balancing but cant figure why the amp with the grids directly
grounded has the filament choke(Japanese) and the floating grids (US)
dont.
I have been looking and cant seem to find the answer. If someone could
comment or suggest a place to look for the answers it would be
appreciated.
Thanks in advance, George KB2Z
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Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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