[Amps] Step Start circuit - needed or not?

[k7fm]

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