Homebrew..
Its a FL-2100B that i scavenged to reuse the power supply and
chassis/cabinet as my base for a 6m amp using the GI-7B triode.
http://www.kb0nly.net/6mqro.html All the info on it...
73,
Scott
----- Original Message -----
From: "Steve Katz" <stevek@jmr.com>
To: "KB0NLY" <kb0nly@mchsi.com>; <amps@contesting.com>
Sent: Friday, March 06, 2009 11:10 AM
Subject: RE: [Amps] A Symptom of Low Bias?
What exactly is the amplifier make/model of the amp (or is it homebrew)?
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]On
Behalf Of KB0NLY
Sent: Friday, March 06, 2009 8:34 AM
To: amps@contesting.com
Subject: [Amps] A Symptom of Low Bias?
Still fighting some small bugs in the new amp this morning, does this sound
like a symptom of the bias being too low??
When i key up with no drive the plate idles at about 90-100mA, and the grid
goes slightly negative, just enough to pull the needle a hash mark width
below the zero on the scale. As i apply drive the plate comes up to about
400mA and the grid starts to come above zero, but i have to literally YELL
on SSB to get the grid to come up and see full output. I tried some CW on
it last night and its making full output there. Also at the suggestion of
some on here i tried applying drive on FM and the grid came up to 100mA and
the plate stayed around 400mA yet.
So from the info i can find online, in the handbooks, picking others brains,
etc.. It would seem i still have a bias issue here as its only amplifying
on the voice peaks on SSB. I dug through my drawers and didn't have the
parts to do the mod for higher bias on the Triode Board so i ordered some
zeners from Mouser today and i will get that done when they arrive and see
if i can further adjust the bias and get the idle current down some more as
well.
What do you guys think?? Starting to realize once again why i like building
stuff, learning is fun!
73,
Scott
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