[mikethedruid]

You're welcome doctormap, but you are still not understanding what is what on the tube. The cap on the top of the tube usually goes to a grid, most often the control grid, of the tube. Look at a schematic of such a tube, and you will see the cap drawn like a little square on the outside of the circle, and sometimes even labeled "cap".

If you look here http://www.r-type.org/pdfs/6k7.pdf you will find a data sheet from the 6K7 tube. There at the top you will see a picture of the tube, and a schematic of it's insides. If you notice you will see the little square I mentioned connected to G1, also, note that pin 1 is labeled "S" for shield, because, lacking a suffix, this is a metal type tube. The remainder of the schematic shows each pin, and what it goes to inside the tube.

Hope this helps