[Arran]

You have to remember that the tube heaters are all 300 ma each times 5 equaling 1500 ma. Is the fiield coil in the B+ or in series with the tube heaters? I kind of doubt that a field coil would draw an amp if it were used in the B+ supply as the #84 rectifier is only rated for an output current of 70 ma, which would also explain the choice of a #41 power output tube. I think the preference for F.C speakers had to do with filtering, P.M speakers of all kinds were in common use in farm battery sets of the era.