Now that i have my amp up and running i find one thing really odd about its
operation, but this may be normal i don't know as i have to wait for a reply
from Ian GM3SEK who i got the Triode Board from which includes the metering
circuits as well.
When i key the amp, no drive, i get about 100mA of plate idle current, from
what i read online this should be fine using the GI7B triode. But the Grid
current meter goes slightly negative, it pushes the needle just a smidge below
the zero mark, and then when i apply drive the Grid meter moves lightning fast
on voice peaks, i mean you can hear the meter going tickety tickety tickety,
etc.
The Plate current meter seems to follow fine. I had to hook up all the old CW
key i keep up on the shelf and with a keydown, short and with pauses to cool
etc, i tuned up the amp and everything seemed to work just fine. Go back to
SSB and again its fine, i just thought it was odd how that Grid meter swings
slightly negative with no drive and then seems to work ok but super fast in
response when drive is applied.
I adjusted my input network a smidge more and basically fine tuned everything
over and over to make sure i didn't miss a thing. I'm now seeing just a needle
width under 500W with 20W of drive, Plate current comes up to about 400-425mA
on voice peaks and the Grid current gets to about 80-90mA.
Anyway, thought maybe someone could tell me why the meter does that little
negative swing? I checked and rechecked the components on the board an
everything seems fine.
73,
Scott KBØNLY
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