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[AMPS] Contemplating Building of First amp

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Subject: [AMPS] Contemplating Building of First amp
From: measures@vc.net (Rich Measures)
Date: Thu, 5 Feb 98 18:13:11 -0800
>I am contemplating a first attempt at building an amplifier.  I am
>thinking of one that could produce a half KW (or more)on all bands from
>160 through 10 meters, be seriously rugged with a heavy duty cycle, and
>yet be made of parts that are readily available.
>
>I have been reading the posts to this reflecter and have been most
>impressed with the kind of knowledge possesed by several participants.
>
>It has become more and more difficult to find interesting projects with
>which to enjoy this hobby 
amen
>(I've built so many antennas), that I thought
>assembling an amp would be interesting, educational, fun, and result,
>hopefully, in a very usable piece of equipment.
>
>I would sincerely welcome everyone's input.  What type of tubes, 
I have some unused Eimac 5-125B pentodes I will donate if you pay the 
freight.  The rating is 200mA each.  The filament draws half as much 
current as a 3-500Z -- 5v@7.5a.  Although the 5-125B may be used in Class 
AB1 grid-driven service, I recommend g-g service.  The socket is the same 
as for an 813, which is available at swap meets.  In RTTY service, one 
tube will put out around 240w max..  In SSB service, one can put out 
around 380w max. . .  At 4kV, the drive requirement is about 25w per 
cathode.  Less anode supply v means more drive needed.  A 5-125B is 
fairly exciting to watch doing it's job.  It uses a tantalum anode.  At 
full throttle, you can read a newspaper by the brilliant yellow-white 
light from the anode.  
-  Some amplifier design info is on my Web site.  
www.vcnet.com/measures
cheers, Doug
Rich...

R. L. Measures, 805-386-3734, AG6K   


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