XLR has been used for years from the box, panels, self-powered, and electrostatics that are powered, and all have never had an issue with balanced gear in my 40 years in this hobby, Clayton is correct fear not, and how this became a concern is beyond me there never been anything written on this for XLR amps use with speakers. Some amps are not truly balanced and that should be a concern, some just use XLR inputs but the circuit is not fully balanced.