[AMRadio] Any amplifier suggestions?

Edward Swynar gswynar at durham.net
Mon Oct 5 12:52:28 EDT 2009

Hi Todd,

A rough rule-of-thumb to help get you started in your choice of tube(s) is
the following: your carrier OUTPUT---when the linear amplifier is used as
such, i.e. to boost the AM signal driving it from your exciter---is equal to
ONE HALF of the plate dissipation of your tubes...

I have a pair of G-G 813s in my HB kilowatt: each 813 is good for 125 watts
of plate dissipation, so one tube alone would be good for 62.5 watts of
carrier output in AM linear mode...the pair of them gives me a total of
125-watts of carrier, with a drive of some modulated 15 watts, or so, at the
linear's input jack...

No, it may not be "as good" to the purists as a full-bore 200 watt plate
carrier modulated by some 100 watts of P-P class B audio, but it'll STILL
make your presence on the band known, and in pretty good fashion, too...

Besides, have you seen many 100 watt plate modulation transformers for sale
anywhere lately...?!

~73~ de Eddy VE3CUI - VE3XZ


----- Original Message -----
From: "Todd Carpenter" <n9ysq at yahoo.com>
To: <AMRadio at mailman.qth.net>
Sent: Monday, October 05, 2009 10:29 AM
Subject: [AMRadio] Any amplifier suggestions?

> I am interested is a simple design hf amplifier for am cw on 160-80/75-40.
These are the bands i operate on where the extra power would help. Fewer
parts count the better. Ultimately lower cost the better. I have power
supply parts and believe that i can generate around 2000 volts. I am slowly
researching tubes and am leaning toward 2 or 4 tubes that can basically
generate lots of watts at half to two thirds their ratings to prolong their
life span. Perhaps tubes such as 811's, 810's, 833's, 4-400's. I am open to
suggestions. I will need to build or acquire a heavy duty matching system as
part of the amp. My goal is at least 300 Watts AM. I do not want to mess
with systems that require cooling other than fans. I am not interested in
modes for this amp other than am and cw. It will almost exclusively be used
for am as i rarely use more than 5 watts on cw any way. Simpler cheaper is
better for me. I appreciate your suggestions. Todd
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