Re: CB amplifiers RM-Italy KL203P

ajparent1/KB1GMX <kb1gmx@...>


Its not so much what they use but how they use them.

I have a Silconix 100W SS (literally CB) amp.  Got it cheap for modding.  Base design is
EB63/Granberg with shortcuts and omissions.   Only a few things wrong with it.  Class B
zero bias (no bias circuit at all) so it had serious crossover distortion Add a regulated bias
and that cleans up. Then it needed varying drive depending on frequency and a seriously
bad input SWR at all frequencies from 3-30mhz.  New ferrite, equalization network plus
a 2db pad to keep it under 1.7:1.  Remove a half dozen mica caps factory installed to
try and calm the amp, added feedback.  Remove the useless RX preamp as it was
noisy and excessive gain.   Add switched LPF.

So why buy it?  The transistors were good (MFR454s), the heatsink and board were good,
and the TR relay worked.   Use it as was, not on a bet (it worked but RF dirty!).   Once I got
done it was a nice clean 13db amp that could run at 100W easily with 5W drive.

Way to many out there like that.


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