[Hammarlund] SP-600 Question

[James A. (Andy) Moorer]

----- Original Message -----
> >James & All,
> >
> >Need some more advice. James, on your site you refer to 47uF, 450V
> >special high ripple capacitors.
>
> Al, James,
>
> I wonder why high ripple caps?  The Hammarlund folks didn't use high
ripple
> caps, did they?
>

In 1954, they didn't distinguish hi-ripple or long-life caps. Who knows what
they might have done with modern caps? My recollection from the Allied radio
catalogs of that day that you just got an electrolytic capacitor of a
certain capacitance and a certain voltage - period.

It is probably overkill to use high-ripple caps there. Only the first one is
subjected to any significant ripple. After the first choke, the ripple is
pretty tame.

I guess it is a matter of rebuild philosophy. I like to try to rebuild these
receivers so they will last another 50 years (although it is unlikely I will
be around to tell one way or another if it worked). One way to do that is to
over-spec the components so nothing is working particularly hard.

---------- anecdote alert --------------------------

I have a friend that built vacuum-tube transmitters that were to operate
continuously and unattended for years at a time. What he did was to reduce
the filament voltage by 10% and use transmitting tubes with twice the
required current-carrying capacity. It increased the tube life to the point
that he had no failures during the service life of the transmitters. Pretty
remarkable.

James A. (Andy) Moorer
www.jamminpower.com