That 25Hz 120VAC power transformer in theory would be happy at 240V at 60Hz. Except that all the secondaries would produce twice their rated voltages (like 12.6V instead of 6.3V). However, the high voltage secondary may get overvoltaged, if it's rated say 500V centertapped, it would produce 1000V centertapped, but the insulation might not take it. Of course the rest of the set won't like it either.
