[Heathkit] SB-200

[Robert & Linda McGraw (K4TAX)]

Inrush protection is typically required where the current rating of a 
transformer is in the 2X or greater value of the operating current.  Heath 
did not over-design these amps in that manner.  Thus the current rating or 
maximum current available at startup is will within safe limits of the tubes 
and transformers.

I think it having worked for some 30 to 40+ years without mods, it is likely 
good for anther 30 to 40 years without mods.

I've never found solid technical reasons for inrush current limiting.

73
Bob, K4TAX


>
> But I do disagree on the current inrush protection
> comment. I highly suggest adding this item into your
> amplifier. It is another potential unit to fail but
> the way I take a look at it is that you can have a
> $1.00 part to fail or a $100 or more part (i.e. the
> power transformer) fail. I think you see the economics
> in this. Besides, why needlessly hammer the power
> transformer with those annoying inrush 'thuds'?
>