[Arran]

The replacement speaker, with the original chassis, is a Utah speaker of similar vintage to the original, early to mid 1930s, it is a field coil speaker, and ironically used in other makes and models of cathedrals, and tombstones. I remember mentioning to Bob on Y.T., after he got this set that not having the Philco pie pan style speaker wasn't a total loss as the replacement probably sounded better. I agree, model 90 chassis are common enough that it isn't worth dealing with a badly hacked up one, especially the mid production ones with the single ended #47, looks like the "Hamster" added a 6.3 volt filament transformer to power the octals he added. The pie pan replacement he has looks like it was paired with a model 20 chassis, those have that big stud, and nut, holding the pole piece in place, but I think the output transformer should still work with P-P #47s or #47s.
Regards
Arran