So how does this fit in with equipment both new and vintage thats designed to be operated and user configerable from 100 V to 240 V?

Does this mean that the sound might vary from country to country?

Are they build to cope with the worst case scenario?

For example the older Stax energisers could be configured for any country in the world bt just chaning a selector and a fuse.

Current EAR valve amplifiers can be configered in the same way.

Any thoughts on this?