true Bill, and a lot lighter and compact. I have power supplies for cameras and external burners and hard drives that are the size of matchboxes supplying 1.5 and 2.5 amps... incredible performance.

The problem is that these have no transformer as such, they switch the mains at high frequency, and filter the result for dc power. The filtering has to be very, very good indeed to get a low noise floor on the dc supply, otherwise that will cause audible problems with the audio signal.

Virtually all home pcs also have these switching supplies and they also contribute 'grunge' to spoil the audio from home pcs and laptops. you need very careful design in layout and filtering to minimise the problems, but it is the way to go, and the problems are not without remedies, only cost constraints