[Amps] 3-500Z heater voltage reduction

[mikea]

On Tue, Sep 15, 2009 at 12:03:21PM -0700, MIKE DURKIN wrote:
> 
> Ok.. yea i did search some on reducing the voltage at the heaters on
>google ... yikes alot of what in not really looking for.So a quick
>question .. what is the favored way to reduce the voltage ?? i have 12V
>ac across 2 at 3-500z's and i want to drop it by -- say 1 volt.
>
> Trying to keep to the confines of what i have around .. some 12 and
>10Ga solid magnet wire, some romex (120v stuff) and some 12ga hookup
>wire witch i dont think the insulation is rated for heat at all ....
>
> Or some other common junk drawer stuff that would do the trick ... the
>last thing i tried was a .27Ohm 10W cement resistor and that was too
>high of a resistance ( was a bit surprised but oh well i dont know the
>internal resistance if the filaments anyways)
>
> KC7NOA ... i think i even have some nichrome sitting round some
>where.....

A small variac off the power line into the filament transformer? May
cost as much as $50, but that's cheap compared to a pair of 3-500Z.
You could stick an AC voltmeter across the filaments, too, and adjust
the voltage using the procedure in "Care and Feeding".

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin