Black spots on clear glass tubes?

bvmjethead · Post by **bvmjethead** » Mon Mar 13, 2006 9:05 pm

I've been looking for some GEC or Genalex KT66's for my 45 build.

I had a guy send me some pics of his pair of GEC's, there are black spots on the bottom of the tubes around the bases, one is larger than the other.

What the deal?

Bad news?

Normal?

Shredder · Post by **Shredder** » Mon Mar 13, 2006 10:17 pm

Some of the KT66s from Genalex had "clear" tops (and similarily nicknamed), and the getter stuff (which absorbs impurities in the vacuum that results from heating the cathode red hot) was around the bottom of the glass, not on top or the sides like other power tubes (6550 or 6CA7).

bvmjethead · Post by **bvmjethead** » Mon Mar 13, 2006 11:52 pm

So some black carbon looking stuff around the brown base is normal.....

wish I could post this pic I was e-mailed...

Shredder · Post by **Shredder** » Tue Mar 14, 2006 1:39 pm

If this is what they look like, you're ok.