[AMPS] Henry 750 SS Amp-More Test

[Tom Hix W4TH]

Hello Vic, 
First off I would like to say it is easy for someone like me to sit here
and give you my opinion when I don't have my hard earned money tied up
in a piece of equipment that may not be preforming as it should, but
having said that, here is what my thoughts are on you problem.
I have been following your reports on the Henry Solid State 750 amp, and
I think it is just a matter of the amp liking the lower end of the
spectrum. I noticed it was producing in excess of it's rated power on
some of the lower bands. 
I have never owned a tube amp that would give me the exact same wattage
on every band. Some of them like 160, and some like 10, but most seem to
be set up to be at their maximum performance on 40 meters, or at least
that has been my experience. But that is on most amps, not all of them.
As I said before some amps are geared for the top end of the spectrum,
and some towards the lower bands. That's just the way it is.
I don't think you have a problem. Of course we all want to get every
watt we can out of our equipment without causing any damage, or being
illegal, but I think you are getting concerned about nothing really. I
mean even if you did get another 100-150 watts out of it, the station on
the receiving end is never going to see the difference. 
If it were mine, I would button it up, put it in place, and enjoy it
just the way it is. Besides all that worry is not good for your
health.....hi hi... 
To borrow an old phrase "it is much to do about nothing"
I wish you well.
73
Tom Hix
W4TH
==================================From: Vic Rosenthal
<rakefet@rakefet.com>
Subject: [AMPS] SS750 output -- more tests 
I'm still trying to figure out why I can only get about 600 watts output
on 14 MHz from my Henry SS750 amplifier (8 x 2SC2879). 
I measured the output into the dummy load with various levels of drive,
from 10 to 100w in 10 w steps. I found the following relationship: 
In     Out 
- ---   ---
10     113
20     216
30     305
40     384
50     427
60     482
70     520
80     540
90     570
100   601 
.... 
150   687 
Obviously, the gain drops as the power increases. Is this normal? 
I did some research, and the 2SC2879 is rated at 13 db gain (minimum) at
28 MHz. with only 12.5v on the collector. The attenuator that's in the
Henry circuit on 14-28 MHz is only 2 db. That should leave 11 db gain.
Allowing for 2 db of loss in the splitter, combiner, and filter, that
leaves 9 db, which should produce 800 watts with 100 watts drive. One
would expect even more gain with 13.8v. 
Something isn't right...I think. I am not a solid-state guy -- help! 
73,
Vic, K2VCO
Fresno CA 
------------------------------

===================================
Be sure to visit my web sites. 

Amateur radio amp tubes.
http://msnhomepages.talkcity.com/ClassifiedsCt/tomstubes/index.html

Ham Radio Homepage.
http://www.geocities.com/Heartland/Woods/6222/



--
FAQ on WWW:               http://www.contesting.com/ampsfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm