i grew up in a time where we had a lot of consumer equipment that had "AC/DC hot chassis" designs. the designers assumed that the outlets in homes were all properly wired. the main problem was that in many instances, the AC outlets were not "keyed", or if they were, they might be wired backwards. this made the chassis, which was supposed to be at or near ground potential, "hot" (at 120Vac).
as long as the equipment was isolated in it's plastic case with plastic knobs, everything was ok. but there were guitar amplifiers etc, that were made this way. when i was young and playing in a band, we did the "plug dance" to make sure everybody's equipment was properly plugged in. we kept a meter handy just to be sure...
even some rather large TV sets used this type of design. all of these devices were vacuum tube devices, and had the filaments wired in series across the line. with tube filaments, there could be a rather large inrush current as power was applied. the power supply itself was only a few hundred milliamps at 150Vdc, as tubes really didn't require as much current. then, somewhere along the line, there began to be regulations and such that required about 1500V or more isolation between the power line and chassis, and many manufacturers who were already switching over to solid state, also went back to transformers. then switching supplies were developed that reduced the need for "big iron" but were able to maintain the high isolation.