I built some 50Hz transformer power supplies when I was younger. :) They were 2x the size of the ATX power supply, produced like 60-100W of power, and weighed s

I built some 50Hz transformer power supplies when I was younger. :) They were 2x the size of the ATX power supply, produced like 60-100W of power, and weighed something like 2kg. Friends building class A audio amps were quite fond of toroidal transformer power supplies, too. They are easy to build, much less complex than switching power supplies. But as others say, less efficient and I'd guess more expensive, these days, unless you have some spare toroid transformer and high capacity low voltage capacitors laying around, already. Just the toroidal transformer for the 800W power supply would weigh like 8kg or so. :)