The Devil said:

Haven't read it. The best book I have is ... ****, I can't remember
the title or the author. I can dig it out if you like. It contains
*lots* of math and is quite advanced, but does start at the beginning,
with materials and thermionic emission. Probably better to start with
something a bit more friendly. Ah, just remembered. Google, Google. If
this is the same website I read a year or so ago (and I'm 99.9 per
cent sure it is), it's a really good primer on everything valves.

http://www.tpub.com/content/neets/14178/index.htm

Thanks Dev, this is an extremely useful site. Bookmarked it
immediately.

--
Sander deWaal
"SOA of a KT88? Sufficient."