On Sep 24, 2006, at 2:18 AM, pentalab wrote:
After all that discussion on the ...'other reflector' about
gettering tubes, I thought I'd add my 2 cents worth.
After reading about the detailled gettering info on Svetlana's
website years ago... I made some enquires.
Svetlana depicted the 4 x getter's on ur typ thoriated
tungsten tubes [metal monsters] as 4 x discs... located at the
TOP of the tube [the pix they had was with the anode cooler
removed].
The 4 x getter's are HEAT activated by the FILAMENT !
I was gonna fire up the filament and blower [NO HV]... and let
it run at rated fil V [measured right at the socket] for a
good 8 [EIGHT] hours.
I use 1-2.5 mh chokes... one per leg.. located right at the
fil lugs to measure fil V. The test leads are brought up to
both a 0-10 vac panel meter... and also some banana jacks [so my
Fluke 87 can be used as well] . I used a 1 k resistor in each
leg + .01 uf bypass cap's at the panel meter/banana jacks. If
the jacks, etc were ever shorted... the resistors would limit
the current.
Then came a ton of e-mail from Economy Electronics + some
amp builders plus a load of 11m QRO builders.
Apparently.... the real method is to run just the filament[s]
{NO HV] for a SOLID 48 hours !!! They all told me my
origional 8 hr plan was flawed... and they had all gone through
this dozens and dozens of times.
After the 48 hrs is up.... HV + drive can be applied.
Do getters stop working when the HV is applied? ... when the drive is applied? ... or when both are applied?
ANY and
all residual gas and junk is absorbed by the getter's... and
you will never get any surprises... like any arcing from
anode to the grounded grid !!
I've fired up several gassy tubes, the insides glowed blue, but none of them arced to the grid.
...
R L MEASURES, AG6K. 805-386-3734
r@...
