Subbing 3AQP1 for 3KP4 with adapter?

[Eric H]

Phil, are you worried about breaking the tube or burning it out?

I was more worried about the latter given the history of that tube and the fact that mine would flare up badly when turned on so I wired in a 6.3v filament transformer.

I forget the part number but it's common and very small, I mounted it using existing chassis holes.