[Amps] Silly idea?

[Kim Elmore]

Here's something I've been pondering, and I'm wondering if it is worth pursuit:

I have an AL80A amplifier (it's stable, but thanks for asking).  The 3-500Z 
in it is the original Eimac tube, and does quite well. The amp has an 
internal Ameritron QSK switch (works great).  I don't want to cycle the 
filament much, so I often turn it on and leave it in "standby" mode while I 
operate, using it only as necessary, which isn't every time I 
operate.  While in standby mode, the filament is running at full voltage. 
One of the limiting factors in filament life is hours of operation, and 
they last a lot longer running at lower voltages.  Of course, emission is 
reduced at low voltages, so I wouldn't want to do this while actually 
generating RF with the amp.

Here's the question: Would it be worthwhile to place a small resistor (say 
something between 0.05 and 0.1 ohm) in series with the filament while in 
standby?  Or is this a no-win scenario, because the small amount of thermal 
cycling would stress the filament enough to send it to an early grave?

73,

Kim Elmore, N5OP

                           Kim Elmore, Ph.D.
                        University of Oklahoma
         Cooperative Institute for Mesoscale Meteorological Studies
"All of weather is divided into three parts: Yes, No, and Maybe. The
greatest of these is Maybe" The original Latin appears to be garbled.