Old Transformers in comparison

[AcquaPanna Panamount]

Hi everybody,
please what about the iron quality, gradation between old Parmeko and old Partridge? which was produced by a harder iron/steel? and which one is so strong and reliable to allow an amp to run without a stand-by switch? [i've heard some rumours telling that if an amp had no stand-by switch, so it was due its own transformers are better in comparison of ones into amps having a stand-by switch; i don't know if that's a ballshit or not]. Thank you all.