ASR-33 conversion to 220V

AFAIK no equipment, either US or European can assume that one side of the mains is grounds (and safe to touch). Therefore a centre-tapped (to ground) supply should be fine. One of my Tektronix instruemnts shows different wiring for centre-tapped-to-ground and one-side-grounded mains (I think only for 230V mains), but this is to reduce noise pickup, not safety, and AFAIK the instrument works if you get this wrong (it just has a little (and I mean little) more noise on the trace). I have a cable here with a 110V BS4343 (yellow) plug on one end and a US mains socket on the other. I use it for running US mains chargers/adapters off a power tool transformer. OK, I only use it for testing (to measure the output voltage/characteristics of the US adapter so I can make a UK mains equivalent, but I've never had any problems running said US adapters off the power tool transformer. [For those who wonder what on earth I am talking about, portable industrial power tools -- electric drills, for example -- in the UK are 110V devices. They're run off a step-down isolating transformer, the secondary of which is centre-tapped with the tap connected to ground. The idea is that if the insulation fails, or you cut through the cable, or, then the maximu voltage you'll get if you touch one bit of metal is 55V (one half of the transformer output, returning to ground through you). This voltage is unlikely to prove fatal.] -tony