Thread: Zero emission?
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Old 1st Aug 2021, 3:03 pm   #1
ITAM805's Avatar
Join Date: Jul 2010
Location: Folkestone, Kent, UK.
Posts: 1,977
Default Zero emission?

On the bench I have a rare 1973 Marshall Master PA, an attic find in a bit of a state. Testing the 4 Mullard EL34's I was surprised the three had zero emission, one had gone to air.

So to check that my little homebrew tester wasn't misbehaving I tried a pair of Edicron's that I bought new around 1990, that I use as reference, one tested as having 50% the other 0%! Oh no, my tester must be broken?

So I got out my stash of used 34's that I had marked the emission on when I put them away, and they all tested exactly as marked? So I retested the Edicrons and yes, they appeared to gone duff?

So what's going on, how could they loose all their go simply sitting in boxes, the getters look OK in both so I'm at a loss. I used them a year or so ago and I noticed that one had slightly lower emission than the other, which had 100%, ironically the one that now has 0%
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