This story brought back memories of a
10x 1625 "amp" me and one of my ham buddies built back in the
mid-60's.? We were 15 year olds with fresh General? licenses and
figured we could make anything work.
It didn't come close to working but the
way it eat up 1625's was entertaining, there would be a little hot
spot on a plate that would travel around until the plate
disintegrated.?? What fun, so we would turn it off and stick in
another 1625 (we had a 50 or so) and watch it burn up.
Eventually we dispensed with turning it
off to add a new victim.? That worked until my pinkie found it's
way to contact one of the loose plate caps and I found myself
flying across the room. smelling of burnt hair.
73 Jack KZ5A
On 4/23/2019 7:52 PM, Steve Ireland
wrote:
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Hi Hans
?
I applaud your ingenuity and QRO does have its place
alongside QRP ¨C a lot
of us do both.
?
In regard to exploding mosfets, about 15 years ago a good
friend, with my
dubious assistance, built a couple of versions of Dave Pick
G3YXM¡¯s Throbbatron
amplifier ¨C see ?
?
In the original
version, after eating a couple of
FETs, my mate got the amplifier working nicely and
stably on 160m CW by using
quite a lot of bias, but I foolishly and insistently
kept pressing him to get it
working on SSB as well.
?
He then rebuilt the amp
with lots of safety
features, removed the bias and, hey presto, it ate IXFH58N20s
in a fairly spectacular and absolutely continuous
manner.? The amp
now sits in a corner of my shed looking sad.
?
There is a lot of black
magic and luck when it
comes to making FET amps. What we learnt is if you get
one working, don¡¯t change
the design!!!
?
Vy 73
?
Steve, VK6VZ/G3ZZD
?
Sent: Wednesday, April 24, 2019 12:29 AM
Subject: [QRPLabs] 50+ Watts am for QCX...
?
Hi all
?
A lighthearted intermission, that I hope you enjoy,
discussing first "WHY"
then the story of explosions, fireworks... and finally a
successful and simple
junkbox amplifier producing over 50W RF from a QCX-40.
?
See
?
73 Hans G0UPL
