Reply to the right laptop

ok, hello folks!

some weeks ago, i played the first time in a club and brought my laptop. however, we had to tape the end of the cable because there was a noise coming from the speakers. the reason for this was some kind of electrical isolation? i didn't understand that part heh..

well, i want to buy a new laptop for myself (the other one belongs to my parents).. now i don't want to buy a notebook that also gets such a noise when plugged in.

so, what should i consider when buying a new laptop?

greets