Laptop Hp Envy 17- J111tx on AC power?

[Harrycr]

Hi I was wondering if REW is ok running on AC power with the laptop listed in the title, battery has no juice left.

Thanks

 

[John Mulcahy]

Sometimes there are hum or noise problems when using AC power, but by no means always. May as well just try it.

 

[Harrycr]

Thanks John.
Other than the obvious hum noise is there anyway of measuring.