>From time to time, we get back to basic arguments that involve philosophy of
>design. Many years ago, I remember that Tektronix often designed their scopes
>to use tubes from certain manufacturers, and found that other brands were not
>suitable. In order to meet their specifications, they insisted that certain
>brands be used in certain positions. And, if the tube was replaced, the tube
>needed to meet design specifications. Was that good engineering practice to
>build a device knowing that plugging in a replacement tube not approved by
>Tektronix might cause the instrument to fail to meet specifications?
>Tektronix thrived during that time period, so it appears the consumers
>answered the question.
And, then there is the Gee Bee airplane. Jimmy Doolittle, flying a Gee Bee,
won a major air race. Problem was that almost every pilot who flew it died.
The design finally disappeared, and all of the history books recorded it as a
flawed design. About 10 years ago, someone from Oregon built a replica of the
Gee Bee. It has a large engine and looks something like a potato with
something like a 10 foot wingspan. It has been pleasing air show fans ever
since, even though it would probably instantly kill most competent pilots. So,
is that well engineered or poorly engineered? The roll rate is fantastic.
Looking at the issue pragmatically, if Carl and Lou are converting amplifiers
that satisfy their customers, isn't that good enough? Perhaps the debate about
whether or not it is good engineering is no longer relevant.
Many years ago, I converted an SB-200 to a 6 meter only amp. I used a separate
input and output and tried to reduce lead length to minimum. Now, that was an
example of poor engineering, because when I got done, it was unstable. That
was before I had much test equipment and I never solved the unique problems of
that amp - created mainly by the 572B tube. Things would have been much easier
had I been using a 3-400 or 3-500 tube. I had just built one of those amps
that was very stable.
Colin K7FM
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