Hi Dave,
Rumors rumors rumors! Someone has been telling you stories!
> amps. MFJ/Ameritron uses their 28V for the 600W solid state amp they sell.
> 18 Months ago the 28V 50A was about $300 and the 50V 70A was about $475.
The ALS-600 uses an old fashioned choke input supply with a swinging
choke. Luke or Lucas or whatever has nothing to do with it. The
supply is 50 volts, and since the voltage is so high a few volts of
drop make little difference one way or another on power.
> I was involved in a discussion several months ago on the contest reflector
> about solid state amps (why there are not more of them on the market).
> Mirage had problems with their 800 and 1500W versions so did not even
> attempt type acceptance as required in the USA.
I looked at the Mirage stuff years ago. Morgan Hills, CA was a
very nice town. But the high power amps didn't fit well in that
town. They used no bias so it was class C, and no output
filter so it was Harmonic Hills on the output. The HF amps
eventually got a creepy bias circuit that made them cleaner if you
didn't run over 100 watts output, but they never did get a low-pass
output filter.
The reason they never type accepted those amps was they were not
designed for Hams. They never would have passed FCC TA.
We all know the "export only" PA's real market. The HF Mirage amps
are now history.
>Ameritron is reluctant
> to bring one out to compete with their AL and new 3CX800 series.
Companies don't mind competition with themselves, but they do like
to see inventory move out the door. High power solid state amps are
EXPENSIVE to do correctly. I've had a 2.4 kW FET amp laying around,
almost in finished form, for several years now. With the switching
supply, direct cost (no overhead related items) is about $3000. That
means a retail of about $4500, and sales of five to ten amps a month.
A large parts inventory (typically 100-1000 piece parts orders are
needed to get good prices) just to make $2500- 5000 a month profit is
not good business sense.
>I found several that make SS amps (one in South Carolina, one
in Ocala, Florida) but
> they all try to stretch 13.8VDC supplies to 90A and don't use 28 or 50V
> supplies.
Never check one of these non-type accepted amps (even kits require
type acceptance to be legal) on a three tone test, either. They have
VERY poor bias supplies, and low voltage transistors are very supply
voltage sensitive. Even with good stiff bias the 2SC2879's are -20 dB
third order below one tone of a two tone. Let's pray they stay in
mobiles, where antenna efficiency keeps them from being band
wreckers.
> OH2BH is supposed to have an amp made in OH but have seen no new
> specs. I notice several use several sections of 250/300W modules for up to
> 1KW...but no one has a 1.5KW output SS amp yet.
OH2BH' s amp looked like a good design, not a CB or mobile use
style.
When 300 volt FET's that work up to 30 MHz get cheap, you'll see
solid state appear. The day is coming faster now, but it still looks
like a long time off.
73, Tom W8JI
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