[AMPS] Misc. Oscillations

[Joe Subich, W8IK]

> measures writes ...
>
> €  A rheostat to adj. fil/heater potential costs under five dollars
> wholesale.  Do any MFJ-Ameritron amps have one?  Would people pay a bit
> extra for such a feature?
>

To be effective the filament rheostat would require built-in metering
with proper RF decoupling at considerably more cost or would encourage
semi-trained appliance operators to operate their amplifiers in a very
unsafe manner (covers off, power on) in order to set the filament
voltage properly.

If you were a commercial amplifier manufacturer, with considerably more
to lose than a bit of wire an a few resistors, what would you do ...
build an amplifier that might require the user to replace tubes a
couple times in 20 years of amateur operation or potentially cost the
user his life and subject the company to a multi-million dollar
wrongful death/product liability lawsuit?

A user with sufficient technical knowledge and concern over filament
voltage issues should be able to easily add the proper rheostat or
filament dropping resistor.  Such a user can probably do it safely
as well, unlike the legion of snake oil buyers.

73,
   ... Joe Subich, W8IK
       <W8IK@Subich.com>
       <www.qsl.net/W8IK>



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