Re: [TCML] Tube question

[Ed Phillips <evp@xxxxxxxxxxx>]

Ed,

I've also discussed my situation with Cameron Prince and he feels that 
my problem is likely with the grid resistance. I am
using a appr. 100 watt rated 0 - 25 K ceramic wire wound
resistor that I have set at 10 K. However, I epoxied the resistor
down to the base and the epoxy has also glued down the "ring"
of the slide tap so I would almost certainly destroy the resistor by 
trying to unglue it and vary the tap. Cameron stated that he
had to bring down the 10 K closer to 8 K to get his 833(C) to
work correctly with his coil after replacing the 833(A). So it
looks like I may have to opt for a high wattage variable rheostat
with a 0 -20 K resistance rating, or something like that.

David"

   I'd try the increased filament voltage first as it's easy to do.  As 
for the optimum value of grid resistor that depends on how much feedback 
coupling you have to the grid and you might also try increasing that 
coupling.  I don't know your physical layout so can't tell you how to do 
that except to say sliding the grid coil closer to the primary increases 
the coupling.

Ed

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