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[AMPS] Plotting of screen voltage variation

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Subject: [AMPS] Plotting of screen voltage variation
From: k7fm@teleport.com (Colin Lamb)
Date: Thu, 23 Dec 1999 08:48:44 -0800
I am presently assembling a test bench to perform "grid-shift"
transconductance testing according to standards set forth in the RCA
receiving tube manual.  I will be using a beam power tube and varying the
control grid and screen grid voltage simultaneously.  Results will be
announced and actual plots will be published.  Equipment set up will be set
forth so that doubters can conduct the same experiments.  After these tests
are conducted, dynamic testing will begin - although that involves many more
variables.

Basic as these tests might be, they will answer some of the questions that
lead us down the path of knowledge.

Assertions by Rich that to question his proclamations transforms one into a
"cultist" seems rather bizarre.  Whether or not one is a "cultist" has
nothing to do with facts.  I have read that N. Tesla had some strange
beliefs - which were generally not only not understood by the average
person, but were totally rejected by esteemed "experts".  In particular, T.
Edison rejected almost everything done by Tesla.  Yet, the outcome of
Tesla's questioning of Edison's generally accepted reasoning and statement
of facts, was a number of useful devices without which our world would be
markedly changed.

I do not know that the G2DAF design is good or bad, and I would not use it
on the air without testing, what I am objecting to is the thought process
and testing procedures of Rich.  They are flawed.  His assertions and
conclusions may be correct - but not for all the reasons stated.

It is true that there are a number of excellent designs for linear
amplifiers that can be copied, and it is also true that the amateur world
could get along fine if no G2DAF amplifiers are ever built again. But if a
faulty process of scientific investigation is used and accepted to reject
that amplifier design, then science will have taken a step backwards by
accepting a process that is flawed.  And, I do find it somewhat dishearting
to have a design from a respected tube engineer (G2DAF) rejected because it
is misunderstood and as a result of a flawed investigation.

As to the point of this discussion and conducting tests of the G2DAF design.
The same argument could be made about almost anything in life.  In college,
I used to run around in a circle for hours every day.  I wondered then why I
was doing it.  It was even worse in the rain and sleet which is common in
Oregon.  In a sense, I did not have enough sense to come in out of the rain.
Sometimes I felt good when I succeeded in competition, but I failed more
often.  Perhaps the best answer as to why this path is taken is simply that
I am now curious and satisfying curiosity makes me feel good (as long as it
is not high voltage).

Merry Christmas and Seasons Greetings to everyone.

Colin  K7FM


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