Pentode (triode connected) in a choke loaded cathode follower...where to connect G3?

[toshiba_nz]

Hello everybody 🙂

I have a pentode (triode connected) in a choke loaded cathode follower configuration ...where do I connect G3 (the suppressor grid)

1. Leave it / NC
2. Tie it to the plate/anode
3. Tie to the cathode
4. Zenner bootstrap it to somewhere (details?)
5. something else

 

[PRR]

Unless otherwise stated "triode" mode is all but cathode and G1 connected to Plate.

Although G3 may not matter much where you put it, if G2 and Plate are good and positive.

Some greybeards thought you should put 100r-1k series to grids to damp push-push UHF oscillations. Others say bah.

There is a side-show. If you want a small triode of moderate gain for low levels and at minimum weight, use 6AU6 taking G2 as "plate" then G3 and real plate to ground/cathode for built-in shielding. BBC did this on some OB (remote) mix-boxes. But not as choke-load CF.

 

[toshiba_nz]

PRR, at least i dont have to get a length of 99.999% pure silver wire, connect one end to G3, wrap it around Venus 6 times, then connect the other end to the moon.😉

Many thanks! 👍

 

[PRR]

wrap it around Venus 6 times,

Seven times for best result.

 

[Miniwatt]

Seven times for best result.

Nahh, 6 times is more than enough. 5 might still do. Lol.

 

[toshiba_nz]

😆🤣

 

[jhstewart9]

There is a side-show. If you want a small triode of moderate gain for low levels and at minimum weight, use 6AU6 taking G2 as "plate" then G3 and real plate to ground/cathode for built-in shielding. BBC did this on some OB (remote) mix-boxes

Like this one at bottom of p790, RDH4? This uses a 6SJ7, I tried it circa
in a small mixer using a 6SJ7, worked well them 👍