> Since when does management listen to engineers?? They
> listen to the mighty $$$$. Just like the Space Shuttle
> Challenger disaster chain of events, the engineers said
> "NO!!", but management said "We'll lose millions!!", so
> they launched with frozen O-rings. We lost more than
> millions...
>
> If you want a "perfect" amp, build it yourself. Better
> yet, let's all do that, swap hardware, and see how perfect
> they are!! Bet you a cup of coffee none of 'em are...
What people forget is amateur radio is not an unlimited
money customer resource like commercial radio, and the basic
use is a lot different. Commercial RF applications have deep
pockets, Hams are cheap. Sales of amateur amplifiers are
almost the inverse square of cost.
Because cost is a huge factor, money can't be wasted on
things that offer no return.
A large factor is use. Amateur amps run a few hours a week
on average. They might get cycled a few times a day.
Commercial gear might be 24/7 52 weeks a year. The service
difference has a huge effect on what expense pays back in
life or reliability.
The very same things that pay back on a commercial amplifier
are totally lost in the noise on an amateur amp.
Filament voltage is a good example. Amateur amps virtually
never have emission failure. Amateur amps also cannot be run
at reduced filament voltage when linearity and squeezing the
last watt out are a concern. They aren't even remotely like
a 4CX5000A running at 2 or 3kW with only 5000 volts on the
anode, where the emission life is the primary source of tube
failure.
A good engineer can sort that all out and make good
decisions, a bad design would include things that never pay
back. One of the best engineered amps on the market was the
SB220. It was amazingly cheap for the results, and they had
a very good service life when operated according to
manufacturing specs. That amp is a prime example of good
engineering for the market place.
By the way, when all the patches and fixes that are touted
as life-improving mods are added to an amp in amateur
service the primary failure mechanisms will still be
uncontrollable. All those cost adding mods wouldn't do a
thing in the big picture. They do keep this reflector busy
by giving people something to complain about.
73 Tom
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