At 11:29 23-03-99 -0700, Dick W0ID wrote:
>
>I never (knowingly, at least) experienced a "Rocky Point bang" until I
>began working external-anode, ceramic-metal tubes, Larry. First the
>3CX1000A7/ 3CV1500A7, then 8877, 8874, 3CX800A7, 3CPX5000A7/3CX15000B7, and
>4CX800A/Gu-74b. Never, so far as I know, with 807(!), 6146, 813, 4-400A,
>4-1000A. Suppose 807 & 6146 are red herrings - 600-750V probably couldn't
>break down the internal spacing short of mercury or neon fill. But with
>4-1000As @ 4-5kV the only Bang!s I could identify came from violent VHF
>parasitics - usually blowing away everything connected to the screen.
Dick,
Thanks for that input. It seems your data parallels my more limited
experiences. One has to wonder what the differences really are. A '30's
vintage 813 surely does not have the metallurgy or process control that an
'80's vintage ceramic-metal tube does. Is it just workmanship or some
subtle aspect of internal geometry?
I got so gun-shy with my bad 4CX1000A experiences, that I used "old" glass
tubes for my last four amps. My latest project is converting the old
4CX1000 chassis to use a YC-156. It should be interesting to see just how
big a "BANG" that sucker will make.
73,
Larry - W7IUV
w7iuv@arrl.net
http://www.axtek.com/w7iuv
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