--- In ham_amplifiers@..., R L Measures <r@...> wrote:
Do getters stop working when the HV is applied? ... when the
drive is applied? ... or when both are applied?
### getter's [per Eimac and Svetlana] are ALWAYS working...
as long as the fil is lit. HV + drive are not part of the
overall process.
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.
### Are u talking about 3-500Z's and 4-1000's ???? [glass
tubes] I have had new 4-1000's that glowed blue. It was
not gas either.... it was an anomoly/defect in the glass....per
Eimac. The glass would glow blue.... only when drive applied.
### Then I have also seen 4-1000's that glowed blue INSIDE the
anode/screen/grid compartment..... dunno if that was with drive
applied or not...... that was too long ago.
### With a big ceramic triode/terode.... I highly suspect... If
it's gassy... and BOTH HV and drive are applied.... arcs MIGHT
occur between anode to screen... or anode to grid.
### If the vac isn't good and hard in the 1st place.... that
could easily create even more problems.
### I had several 4-1000's yrs ago... that looked like a smoke
bomb going off inside.... when the fil V was applied!! They had
either a lousy vac.... or..'had gone to air'.
### did u ever see a blue glow inside the ceramic portion of a
metal tube ?? Kinda tough to see..with the chimney on.
### All I was trying to get at was.... if 16 guys say to use
48 hrs to getter a new/rebuilt tube.... and anything less is
gonna be a problem... cuz they have tried many diff time
frames... who am I to argue?
### Svetlana claims their tubes are proccesed at a higher temp
than Eimac [during the construction of the tube]... one would
think the Svetlana tubes would have less of a 'gas' problem
than an Eimac ?
### The Svetlana tubes all use a 'spiral mesh fil' and
where all the mesh criss crosses... they are welded. ... so
u don't wanna slam the fil V on.. it can buckle the mesh fil
sideways..esp with over rated fil xfmrs [eg: I use a 80 A
rated fil xfmr on my 50 A rated 3000A7]......... another reason
to step start em.
## I don't have the time or patience to inadvertantly destroy
expensive new/rebuilt tubes.
Later... Jim VE7RF
...
R L MEASURES, AG6K. 805-386-3734
r@...
