When connecting loudspeaker systems, please mind the polarity according to the following diagram: GROUND-LIFT SWITCH The ground-lift switch allows eliminating noise loops. If the power amplifier is operated together with other equipment in a 19“ rack-shelf, setting the switch to its GROUNDED position is recommended. If the power amplifier is operated together with appliances with differing ground potentials, setting the switch to its UNGROUNDED position is recommended. REAR VIEW LIMITER The inte