Originally Posted by Kevin Dougherty
I don't think it works this way though, because the output of each supply isn't dependent on the output of the previous one... each one is independent. It would be like that you had several in a series that halved the voltage like: 96/2 @90% -> 48/2 @90% ->24/2 @90%...
But 12+12+12+12 @90% each should theoretically be the same as 48v @90%.
12v output @ 350ma is 4.2w output, meaning 4.62w had to go into it.
4.62 + 4.62 + 4.62 + 4.62 = 18.48w for 16.8w output in a series.
Now whether you'll find a cheap, small output supply that efficient is another thing (not likely, IMO).