Tube socket center post

[bequerel]

I have noticed that some tube sockets have a center post. Since this is not connected to anything on the tube itself, what is this post used for. I suppose that it goes to ground, but what does it do?

 

[DF96]

When grounded (as it always should be) it reduces capacitive coupling between tags/sockets. Most important for RF; less so for audio. Some RF circuits may use it as a local star point, as RF often uses a star per stage.

 

[JonSnell Electronic]

Normally it is used as a star point.

 

[bequerel]

Thank you so much, guys. 🙂