If the inrush current is so great that there is a large power surge, then
in-rush protection is a good idea. In many cases, this is desireable in
home-brew amps, where surplus and oversized components are used. In many
commercial amps, the transformers and capacitors are sized "just right"
rather than oversized, and the surge is less of a problem.
In some older amps, however, the on-off switchs are becoming unobtainable,
and in that particular case, it may be useful to give extra protection for
that switch (or use an external switch). Consider the 120 volt light switch
in your home. Lamp resistance of the incandescant lamp is very low at
turn-on, which can stress the light switch and the bulb. That is not a big
deal, because light switches are cheap, as are light bulbs. Perhaps, with
the ban of sale of incandescant lamps, we may find ourselves installing
in-rush protection for our lamps. Or we might have some company start
selling old radio tubes with big filaments, to get around the incandescant
lamp ban. Imagine a compact fluorescant 304TL!
73, Colin K7FM
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