Most of the American/Canadian manufacturers these days are using dual wound power transformers, which just need a wire swap to change voltages. There is unfortunately no way tell from the outside, and the best thing to do is to call the manufacturer and ask :-( As for older used gear, you can usually open the top cover, and look at the transformer. If it is dual voltage ready, there will usually be some clues, such as a diagram, open transformer connections not connected, loose wires not connected, etc. Happy Listening, Arnie
