Well, yes and no. The amp side runs on two separate power supplies one for each channel. They are heavy ,at 70 lbs each. The battery is only for the input stage. This units weight is around 45 lbs. When the unit is OFF or in STANDBY the battery is in the charge mode.
When the unit is in the ON (position one or two , the unit has two volume positions) the battery is then being used for listening. The battery is then diconnected from the line voltage charger via a relay. This way no ac in the unit to screw things up in the line stage.