Considering that a lot of interesting power pentodes and BPTs have fairly close control grid to screen grid spacing, which may preclude proper triode strapping or Ultralinear operation, I was thinking, just how well would (or would not) simply connecting G1 and G2 together for an alternative triode mode.?
This was done in the "daze of olde", with the 46 and 51 "dual grid" triodes, would it work with more modern power tubes? I guess there is really only one way to find out, and that's to give it the old smoke test and see and listen to what happens...
One other "weird" triode mode I've seen is to ground the G1 grid, and then use the G2 grid as the signal input grid, this may be quite useful in direct-coupled circuits.
/ed B in NH