[Kenwood] TS930/940 PA modules.

[Dr. Gerald N. Johnson, electrical engineer]

The 930 and 940 use 28 volts on the PA and driver transistors like some
other radios of that and more recent eras. That allows for a bit more
power and better linearity.

There is a company that sells kits for amplifiers based on Motorola
applications notes, some bipolar, some MOSFET. RF parts sells them too.
It would be sacrilege to scrap the 28 volt amplifiers and power supply
and drop in a 12 volt amplifier, but the 12 volt PA at 100 watts output
seem to be less prone to self destruction. Some of the MOSFET amplifiers
are very good and run better on 28 volts.

One should be wary of the 28 volt power supply. If it gets high from
shorted pass transistors, I suspect the PA and driver transistors go
soon afterward from over voltage.

Then while they can't sell it in the US as a kit, Elekraft makes a 100
watt 12 volt amplifier too that might be arranged to drop into classic
solid state radios.

I've not tried any of these, just throwing out some ideas.

73, Jerry, K0CQ

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Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
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