[Arran]

The 25 cycle sets usually had larger value filter capacitors and possibly a larger filter choke but the rest of the parts were the same.

Except for the power transformer. A transformer designed for 60 cycle operation will burn up at 25 cycles. However, a transformer designed for 25 cycles runs fine on 60 cycles.

Of course, the power transformer as well, but I assumed that they were asking what else might be different other then the transformer. The area that I am in used to have 25 cycle power at one time, the coal company built a power plant and that was what they used around here until 1957 or so. The transformers were no problem in the switchover but of course the motors were, a 25 cycle motor will try becoming airborn on 60 cycle. The people who remember it say that the light bulbs used to flicker in the corner of your eye and things like the washing machine ran really slow, that doesn't make much sense since it would depend on how the motor was wound.
Regards
Arran