>>From where things ended up, it looks like some body of
> people say that the grid fuse/resistor idea really works
> and they are convinced their experience proves it.
>
> There is another body of people that use
> reasoning/logic/etc
> to say that it could never work.
>
> I myself have a bit of a hard time with the universal
> negative: "that will never work" type of argument.
> But I appreciate that folks on both sides have a lot
> more experience that I do.
No one I saw ever said "it won't ever work" in the sense
that the user would notice a problem.
What most people said is it is a very bad idea, certainly
not the best way to protect things, and may actually be
harmful.
There is a huge difference between the two statements. Many
things are useless, bad ideas, folklore, and/or so far as
technical description absolutely wrong and although being so
it still doesn't mean they "won't work". I can, for example,
remove two lug nuts on my car's wheels to reduce the number
of flats and not observe any problems. I very well might
have less flats, and conclude it actually works. A vocal
snake oil salesmen might remain popular among a few people
because a few took the oil and honestly felt they were
cured.
My wife's brain works that way. I see it in action every day
at the mailbox, shake my head, and move on.
> The real lesson for me was that there is such a
fundamental
> disagreement on what is going on inside that little glass
> box. It definitely doesn't look like settled doctrine.
> And that's OK with me, I can live with a little bit
> of ambiguity.
In scholarly text and peer reviewed engineering text and in
laboratory tests there is virtually no disagreement. There
will always be one or two very vocal people who find ten's
of thousands of hours of rigorous experiment and the
collective minds of the rest of the world wrong.
> The floating grid issue seems kind of intriguing.
> Maybe I'll get out some old octals or something and play
> around with that and see what happens. The "Tubes 201"
> guy seems to go both ways, one sentence says never float
> the grid, and the next sentence seems to allow for it.
So do engineering texts. In small very low level tubes,
contact bias is a valid bias method. In high power tubes or
systems with higher voltage levels, engineering texts warn
against it. It all depends on the application.
Then easiest thing in the world is to give a clear-cut
explanation that says "it is this way all the time". It
sounds authoritative, especially when mixed with accusations
of dishonest by big business and conspiracy of engineers and
professionals to hurt one person. Over the years I've
learned when one or two people claim nearly everything
everyone else has done is wrong, they are generally involved
in some sort of voodoo science. It's a red flag to look
closely.
73 Tom
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