What is difference between strapping the screen grid to the anode or cathode?

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jackinthebox

Member
Joined
Jul 2, 2011
Messages
24
This is my first post here so i apologise in advance if this a newbie question.

I have noticed that in different mic circuits using a strapped pentode design sometimes the screen grid is strapped to the anode, like in a VF14 in a U47 circuit, and sometimes it will be strapped to the cathode.

Can someone explain this please? I am about to install a Raytheon 5702WB valve in place of a 6C31b-p submini and i just want to make sure i am strapping the correct legs together and wanted to clarify what the different kinds of strapping gives one in terms of performance of the valve.
As far as i know the suppressor grid (3) needs to be strapped to the cathode so does that mean the screen grid should be at the same potential and also strapped to the cathode?

I also have a similar question regarding the Mullard CV465 valve and how ones goes about strapping it for single triode use.
I believe the pin configuration is:
1. Grid 1
2.Cathode and Grid 3
3.Heater
4. cathode and grid 3
5. Anode
6.Heater
7.grid 2
8. cathode and grid 3.

Do i connect together pins 2,4 and 8 or cut 4 and 8 short? And where does that grid 2 need strapping to again?

I don't want to ruin the valves or my circuit so i'm being extra cautious.

thanks i advance for any help.

I did several searches on this subject but haven't been able to find a definitive answer.

jack
 

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