General Troubleshooting Tips - Bose AmPlus 50 Supplement Manual

GENERAL TROUBLESHOOTING TIPS

Guidelines for wiring to and from the system electronics
• Always use shielded cable and follow the wiring diagrams in the Installer's Guide, Bose
number 191911.
• A cable with braided shield is preferable to one with a spiral or foil shield.
• Keep the input wiring distant from AC mains wiring.
• Keep the input wiring distant from loudspeaker wiring.
• Never bundle input and loudspeaker or power wiring together in the same jacket, or with
lacing twine, or in the same conduit.
• Do not connect the input signal grounds to either side of the loudspeaker output.
• Place the source equipment as close to the system electronics as practical to keep the
wiring short.
• Whenever possible, use source equipment with balanced outputs, and receive it at Music
Input A balanced.
• If the source equipment must be over 12 feet (4 m) away, and is unbalanced, equip it with a
balancing transformer to convert it to a balanced output.
• Note that in most of the wiring diagrams given in the Installer's Guide, Bose part number
191911, the shield of the cable is connected only at the source end. It is poor practice to
ground the shield at both ends, because then it serves as a conductor and radiates
interference into the center wires. With unbalanced sources and pre-wired RCA-RCA plug
cables, the shield is grounded at both ends. However, cables with two-conductor shielded
wire , using the two wires for hot and ground, and grounding the shield only at the source
end may perform better.
Balanced Source Terminals
• The signal outputs of equipment with balanced outputs consist of three terminals. The
positive (+), the negative (-), and the GND (or COMM or COM). The audio signal it applied
across the (+) and the (-) terminals as a voltage. The (+) and (-) outputs may or may not be
referenced to the GND terminal. The receiving equipment input, if balanced, should respond
only to the voltage difference between the (+) and (-) terminals. This leads to improved
rejection of interference picked up in the cable.
• Screw terminal - Each output of the source equipment has a positive (+), a negative
terminal (-), and a GND terminal. Connect the cable to these terminals. On some equipment,
a chassis ground screw or bolt may be found. Do not use this ground point as a signal
ground.
•
Phone Connector - This connector will be 1/4 inch in diameter. The sleeve of the connector
is always used for GND. The tip carries the (+) side of the signal, and the ring carries the (-)
side of the signal.
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