100v,115v versus 230v

The whole world should standardize on 300 volts RMS at 100 cycles.  Running at higher frequencies increases transformer efficiency.  Everything would interoperate.  Just do not stick your fingers into the outlet :-)

@ditusa THANK YOU,  surely will do,it has been rather educational for me , esp, how vicious 9 volt battery can be be.

Yes we in Europe is blessed with better sounding systems in general. ;)

But you in the US use higher amperage fuses in your equipment and they sound better!
And the us power plug is probably a better, firmer fit in the receptacle than the round blades of Schuko in mainland Europe.

220 is more efficient than 110.  Three phase is more efficient than 220.  110 is less likely to kill you.  The duration between pulses is longer on 110, and you will have more time to escape the grip of electricity stopping your nerve impulses.  At the same watts, amperage is lower, the lower the voltage.  That is why a car uses up to a 1000 amp fuse on a 12 volt system.  1000/12 is only about 83.33 watts  A 20 amp 110 volt circuit is 2200 watts; 240 v is double that, and can be 50 amps in a house stove or A/C, or 5500 watts of killing power.  DC gives no time in between pulses for your nerves to control muscles.:  You can't escape unless you accidentally fall and gravity pulls you away from the current source, such as a wire.