In a message dated 98-06-25 18:53:27 EDT, you write:
<< And in that same 12 years I've know one ham to have rebuilt his Astrons
twice and others to have done it more often from failures of pass
transistors. Running 22+ volts unregulated and wasting all the power in
poorly cooled transistors to drop the voltage to 13 volts isn't my idea
of energy conservation. It amounts to nearly a 50% power waste, measured
from the input. Compared to the output power it means nearly as much
wasted as supplied to the load.
I've fixed one Astron (bad 723) and had two that have never broken (all over 8
years old). Keep in mind that the efficiency of a linear supply is only a
significant issue if the power supply is delivering a lot of power over a long
period of time. I'd dare say that an amplifier in SSB service does not pull
much average power. I would be surprized if the Astrons would heat up much.
Average power is probabably not more than 50 watts.
The problem with using a battery is that the voltage will drop off quickly.
Operating voltage to the amplifier is more like 11-12 volts after IR losses in
the cable, etc. At such low voltages the amplifier may behave unpredictably.
My recommendation would be either to invest in the Ten Tec power supply or to
use a 70 amp Astron.
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