>Many years ago I found an old Swan Mark ll amp in a flea market.
>The amp was pretty big, made of steel and had a good looking front
>panel. Thinking it would be a great box for a home brew amp I got
>it cheap. When I got it home and looked inside it didn't look all
>that bad. Actually pretty good. The tubes were gone (of course) so
>I stuck in some new ones and let it rip in a CW contest.
>
>BLAM went the transformer! They used the same transformer for both
>control, filaments and HV. They guy that owned it said he used it
>for YEARS and sells it to a contester where it lasted 1 hour.
Well, I guess I had a _little_ better luck with my Swan MKII. I've
used it in several SSB contests, and it did rather well. The airflow
really is poor for contest-duty though. Found that out the hard way.
We had used it one year for CQWW on 40M. Noticed that the power output
was low. Oh no...a filament was out! Turns out that it got so hot
that the solder on the tube's filament pin reflowed!
The amp was used again just recently for a backup for a CQWW M/M. Was
going good until the transformer began arcing to the core.
Replaced the transformer with one from Peter Dahl. Pegs the voltmeter
and almost does 2KW with 100W drive. Definitely needs more air now.
I've also ran the amp at 3500+ for HV and have never had an RF deck
arc, pop, or anything.
Other than not having 160M and not enough airflow, the RF deck, I think,
is rather solid.
---
Chad Kurszewski, WE9V e-mail: Chad_Kurszewski@csg.mot.com
The Official "Sultans of Shwing" Web Site: http://www.QTH.com/sos
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