Other issue is that your electronics be connected to a full regulated electrical line and that the system been grounded at only one " point " been sure that the ground be a phisical true earth/ground.
Batteries? forgeret about: if your electronics has a good power supply design then it will performs better than batteries.
Batteries is another sneak oil products used by very low knowledge levels. All is besides the power supply electronic design.
An item with poor power suply design obviously that always will sounds better.
Some " audiophiles " as pauly lives in wonderland audio and are really untrusty as in this specific regards.
Your call. Mine is only an additional opinion.
Regards and enjoy the MUSIC NOT DISTORTIONS,
R.