Rotel

No small feat in this day and age, Rotel is still privately-owned by the original family that founded it in the 1960s. 

One of their key selling points is the fact there is a stunningly low failure rate of the on-board toroidal power supply. Rotel attributes this reliability to the fact Rotel are one of very few companies to still build their transformers in-house, guaranteeing the manufacturing process from the get-go. 

Because of this, at Rotel, we can be certain of the purity of steel & copper materials as well as the number of windings that each power supply receives, ensuring that these transformer are in fact, over-engineered.