Sweep tubes and G3

[rsumperl]

Greetings,
There are some sweep tubes that have G3 separate from the cathode connection. Is there any advantage to having a small positive voltage on G3 instead of grounding it? On the tubes that have G3 separate, some of the tube sheets suggest 30 or so volts.

Thanks,
Ray

 

[Tom Bavis]

Search this board for "snivets" or"Barkhousen oscillation" for some interesting reading about the original use of these tubes...

 

[DualTriode]

Hello All,
I would say that G3 is another electrode to play with. Who knows how many watts it can dissipate before it blows up. Perhaps G3 drive? Perhaps a place to inject feedback?
More grids is equal to more variables = combinations and permutations.
Plan out a few what ifs and hook one up to a curve tracer.
DT
All just for fun!

 

[smoking-amp]

g3 doesn't have much effect for control use except in some special dual control tubes which have a fine mesh g3. Take a look at this link on g3 effects:
http://www.diyaudio.com/forums/tubes-valves/160240-suppresor-grid-used-feedback.html