How to triode strap pentodes?

Hi,

I am a tubey newby so forgive me if this is trivial or it has been discussed before. Recently I found a dozen Sylvania 6BX6 (EF80) pentodes. Can someone help point to a resource where I could learn how to connect them as triodes?

Thank You,
Tamas

The usual way is to strap the screen grid to the plate, either directly or (in the case of power tubes) through a current-limiting resistor.

Here are curves for an EF80 as a triode:

http://www.tubes.mynetcologne.de/roehren/daten/ef80pentode_as_triode.pdf

..or look at the G7 mic schematic, it's an EF86 triode-coupled..

One thing I am tring to find more information on is why some pentodes as triodes have G2 and G3 to the plate VF14 in the u47 and others have G3 to the cathode and G2 to the plate, EF86 in the u67

Sometimes the G3 screen has an internal connection to the cathode.

The only thing I found was a short part in the big red book, if I remember right it has something to do with noise. I guess do to the different internal costruction?

Thank You All! I just got a Heathkit tube power supply to start dorking with this stuff. :green: