> The subject has come up in the other thread about good
> amplifier design,
> attention to what is "right" and "wrong" etc. I would
> like to know
> HOW....if....grounding grids through caps like Heath
> SB-220 and Drake L4B and the Collins
> amps and others was a poor design, why did so many pick up
> on the idea and
> do it?
I've explained that dozens of times.
Bill Orr copied that idea from Collins. He totally
misunderstood and misapplied a great idea Collins had for
the AB1 tetrode with grounded screen in the 30S1, and
wrongly applied it to AB2 (grid current) amplifiers that
used triodes.
Bill used to hound the hell out of people trying to get them
to use his pet idea for "super cathode driven". He called
Ameritron and insisted we use it, he called Heath and did
the same. The only way I stopped it from being used was I
actually measured it in a few amplifiers and took data, and
the hard data showed it destabilized the amplifiers, made
them more sensitive to loading, reduced the gain flatness,
and generally increased IM.
> How could something that is NOT considered "good" gain so
> much
> popularity?
Because of pressure. The same pressure is being applied with
nichrome. A forceful or popular fellow gets an idea, right
or wrong, and he hounds and torments people until they
yield. A good example of this is the folded monopole antenna
in Orr's handbook. It is VERY easy to demonstrate the idea a
folded element reduces ground loss is without merit. Both
W7EL and myself independently (years apart) demonstrated
that to Orr, and Orr agreed. But the idea never came back
out of the West Coast Handbook. The same is true for the
"super cathode" nonsense.
An even larger problem is once something gets in print, even
if totally wrong and removed later, it takes on a life of
its own. An example of that is the silly "shielded ground
lead" idea, or the idea that moving a 1:1 balun from the
output of a single ended floating network tuner somehow
improves balance.
There are a lot of easily proven wrong ideas that live on
and on because they either make it into publication or are
driven by a person with a particular agenda. Sometimes
manufacturers, even though they know better, just go along
because the market views an incorrect idea as good.
That's the way life is.
73 Tom
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