Rives suggestion is an excellent one. Perhaps one suggestion to add to Rives: if you are able to convert your equipment, especially the amp to 230 volts, then you would not need a step down voltage converter. Instead, you would have some of the best AC you could practically muster. But this last step takes know-how and gonads but is cheap with excellent results.
Your electrician or perhaps Rives could best answer your question about isolated grounds.
-IMO
Your electrician or perhaps Rives could best answer your question about isolated grounds.
-IMO