[. . . ] Heed all warnings and safety information in these instructions and on the product itself. You must allow 10 cm or 4 inches of unobstructed clearance around the unit. Do not place the unit on a bed, sofa, rug, or similar surface that could block the ventilation slots. If the component is placed in a bookcase or cabinet, there must be ventilation of the cabinet to allow proper cooling. [. . . ] There should be 10 cm (4 inches) of clearance around the chassis, and reasonable airflow through the installation location, to prevent the amplifier from overheating. Remember the weight of the amplifier when you select an installation location. we recommend installing the RA-820BX3 in furniture designed to house audio components. Such furniture is designed to reduce or suppress vibration which can adversely affect sound quality. Ask your authorized Rotel dealer for advice about component furniture and proper installation of audio components. The RA-820BX3 does not draw high levels of current from the power outlet. However, whenever possible, it should be plugged directly into a 2-pin polarized wall outlet. A heavy duty multi-tap power outlet strip may be used if it (and the wall outlet) can handle the current demanded by the RA-820BX3 and all the other components connected to it. Your RA-820BX3 is configured at the factory for the proper AC line voltage in the country where you purchased it (either 115 volts AC or 230 volts AC with a line frequency of either 50 Hz or 60 Hz). NOTE: Should you move your RA-820BX3 amplifier to another country, it is possible to reconfigure it for use on a different line voltage. Opening the enclosure of the RA-820BX3 exposes you to dangerous voltages. If the turntable has a "ground" wire connect it to the screw terminal to the left of the Phono inputs. The polarity ­ the positive/negative orientation of the connections ­ for every speaker and amplifier connection must be consistent so all the speakers will be in phase. if the polarity of one connection is reversed , bass output will be very weak and stereo imaging degraded. The wire may have clear insulation with different color conductors (copper and silver). These are for connecting components such as CD players, Hi Fi or NICAM Stereo video cassette recorders, tuners, Laser Disc players or the analog output from a CD ROM drive. The Left and Right channels are labeled and should be connected to the corresponding channels of the source component. use high quality RCA cables for connecting input source components to the RA-820BX3. The speaker outputs are controlled by the switch 5 on the front panel. Turn off all the components in the system before connecting the speakers. The RA-820BX3 has colorcoded binding post type speaker connectors on the back panel (except in European Community countries where their use is not permitted). These connectors accept bare wire, connector lugs, or dual banana type connectors. [. . . ] For best performance, you may want to consider special high-quality speaker cables. Your authorized Rotel dealer can help in the selection of cables for your system. The Phones output allows you to connect headphones for private listening. If your headphones have another type of plug, such as a 1/8" mini-plug, you will need an adapter plug. [. . . ]