In article ,
AndyW wrote:

I have picked up an old radio that I plan on restoring but it is valve
based and I am a child of the transistor era.
I understand the physics of the basic thermionic valve and the grid but
once they start to get multiple grids and screens in there I am lost.

Can anyone recommend a good website primer on valves / vacuum tubes?

Andy-

As Philo mentioned, the information you are looking for is most likely
to be found in books published before the mid 50s. A couple you might
look for are old editions of "Radio Amateur's Handbook" and the
"Radiotron Designer's Handbook".

Although it may not be the primer you want, a PDF copy of an RCA Tube
Manual is at http://www.tubebooks.org/tubedata/RC15.pdf.

Fred
K4DII