|[AMRadio] Speech processing technologies and methods?|
ka1kaq at gmail.com
Fri Dec 20 11:58:39 EST 2013
On Thu, Dec 19, 2013 at 10:33 PM, Brett Gazdzinski <b.gaz at comcast.net>wrote:
> I hear people say stuff like this all the time, and I do not understand it.
Perhaps that means there's something to it?
> The only problem I ever heard of with the 32V series is the overloaded
> filament power drawn from the
> low voltage transformer.
> I solid stated all the rectifiers 30 years ago, run mine on the 700 volt
> tap, and nothing has ever gone wrong with it, its still got the same tubes
> in it that it came with.
Okay in the 30 years since you've SS'ed the rectifiers, there's been a
pretty large resurgence in AM activity. As a result, a lot more 32Vs have
come back to the surface, dug out of basements, barns, and garages, and
gotten pressed into service. I'll be not many of them had a lot done to
them (mine didn't, it was in great shape when I bought it for $40 in 1990
and worked fine). So add a few more decades to the age of components and
transformer insulation, along with elevated line voltages. Seems easy to
If yours has never broken, you're lucky. Mine has blown up (literally) the
same oil cap twice. The first was the original 1940s cap. The second was an
original out of a scrapped transmitter, same age. It blew up too. Found a
newer one at the Shelby hamfest and installed it. No more problem.
> I run three 4d32's at 1250 volts in one rf deck, so voltage is not going
> to hurt them!
> My low voltage transformer runs cool, nothing seems to get hot in the rig
> at all.
Considering you've removed a fair amount of the load from it (and nearby
heat), that's easy to understand too. The low voltage transformer failure
is well documented from numerous repair sources as well as by folks who
have had it happen to them. Stick the tubes back into yours and use it for
a couple hours daily, then see how long it lasts. Maybe your luck will
~ Todd, KA1KAQ/4
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