Hello !This is something that has been on my mind for a while.Why is it that tubes such as the 6L7,6K7,6A7, 6Q7 etc.... lost their grid caps and had the grid connection placed under the tube later such as 6SA7,6SQ7 ,6SK7 etc....I read that the grid connection was placed on top for a reason (to keep it farther away from other parts of the tube(capacitance??).Also on top of that ,what about miniture tubes that are even smaller and more compact??????It doesn't make sense. I love the grid cap tubes they look cool!

:Hello !This is something that has been on my mind for a while.Why is it that tubes such as the 6L7,6K7,6A7, 6Q7 etc.... lost their grid caps and had the grid connection placed under the tube later such as 6SA7,6SQ7 ,6SK7 etc....I read that the grid connection was placed on top for a reason (to keep it farther away from other parts of the tube(capacitance??).Also on top of that ,what about miniture tubes that are even smaller and more compact??????It doesn't make sense. I love the grid cap tubes they look cool!
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They changed the grid connection on the top cap to the plate connection. They thought it would be a great joke to play on techs who were in the habit of touching the grid cap to test for noise and hum. Just stick your finger on a plate cap once and you'll never forget the experience.
Johnnysan-

It sure is handy in determining what stage has the problem before pulling the chassis out of the cabinet.
A coax shielded grid cap connector wire and tube shields would also help keep feedback noise down.
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As tubes got smaller, the grid connection at the base got shorter, so that capacitance to the other leads wasn't a problem. Single-ended tubes were cheaper to build.

:Hello !This is something that has been on my mind for a while.Why is it that tubes such as the 6L7,6K7,6A7, 6Q7 etc.... lost their grid caps and had the grid connection placed under the tube later such as 6SA7,6SQ7 ,6SK7 etc....I read that the grid connection was placed on top for a reason (to keep it farther away from other parts of the tube(capacitance??).Also on top of that ,what about miniture tubes that are even smaller and more compact??????It doesn't make sense. I love the grid cap tubes they look cool!
:Thanks Gentlemen!!