100v,115v versus 230v

Excellent info ! an american scientist friend also shared this additional explanation to me example of Kettle and hot tubs,,,

110-Volt Hot Tubs

• Pros: Have a 110-volt power outlet? Score! If you’re in the United States and you’ve plugged any type of electrical device into a wall outlet then you have the necessary socket to run a 110-volt hot tub. So, just fill with water, add your hot tub chemicals, and enjoy!

• Cons: What’s 220 divided by 110? No need to bust out that calculator; the answer is ‘2’ and that means it will take twice as long to heat up a 110-volt hot tub as it will to thermalize a 220-volt hot tub. To add further insult to injury, the amount of time your pump runs to circulate the water will also double (compared to a pump in a 220-volt system).

Questions remains, if 220 volt has more guts and torque does High end equipments sounds better at 220/230 volt ?

Audio gear such as amps, preamps, tuners, CD players etc typically have transformers inside. Whatever the line in voltage is, that line in voltage is changed to whatever the component actually runs on 

"To add further insult to injury, the amount of time your pump runs to circulate the water will also double (compared to a pump in a 220-volt system)."     WRONG!   The typical, dual voltage, AC(single phase) electric motor, when attached to a pump, runs at the exact same RPM and HP (https://spicerparts.com/calculators/horsepower-torque-calculator), wired for either voltage.      The only thing that will change, is the current draw, which will drop by half, at the higher voltage.      ie: https://www.youtube.com/watch?reload=9&v=3llc68VvzsY     Notice here, that though the motors are all dual voltage; only one RPM is mentioned for all and one HP rating for each, in the specs: https://www.poolblu.com/Public/pbsShowFamily.aspx?xFM=FM043298&xCT=

Some of my  japanese friends who they live different part of japan where voltage is 200 volt they say their audio gear it sounds better then 100 volt supplied areas.Known fact all the audio gear has transformers except OTL Amps etc, another person I know who he Returned from USA brought his  120V ARC REF 610 Power amps to UK He is saying that he is getting better results using step up/ down device.

Sounds like an Ask Paul episode.
He could easily compare his own stuff with a Power Plant and identical amps set to Schuko.