Parasound A 31 manual Audio Connections, Audio Input Connections

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Audio Connections

Always disconnect the AC cord to your A 31 before making or changing any input, output or trigger wire connections. Inserting or removing an input or output cable while the A 31 is turned on can result in a blast of sound that can damage your loudspeakers. Make sure there is no strain or tension on any cables that could cause them to pull loose.

Audio Input Connections

Balanced XLR Input Jacks

Balanced connections will give you the best sound. If your surround sound preamplifier has balanced XLR output jacks, we recommend that you connect them to these inputs. Refer to the Balanced and Unbalanced Lines in the Technically Speaking section for additional information about why we recommend using balanced lines.

Unbalanced RCA Input Jacks

Use these inputs if your surround sound preamplifier doesn’t have balanced output connections or if you simply prefer to use unbalanced connections.

Balanced/Unbalanced Selector Switches

Place the switch in the position for the input type you will be using.

Note: The Balanced/Unbalanced switches are not input selectors. Their function is to optimize the s/n ratio for each type of input. You should not connect both the Balanced and Unbalanced jacks at the same time with the expectation of switching between to different signals.

Balanced XLR Pin Configuration

The balanced inputs of the A 31 use XLR jacks that conform to the industry standard of:

Pin 1: Ground Pin 2: Positive (+) Pin 3: Negative (–).

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Contents OWNER’S Guide Important Safety Instructions Table of Contents Thank You for Choosing Parasound Important Warranty informationParasound Staff Keeping Records for Future Reference AC Mains Voltage Unpacking Your a 31 & Placement GuidelinesUnpacking Your a Rack Mounting Your Parasound a Audio Input Connections Audio ConnectionsCorrect Speaker Polarity is Important Speaker Wire Length and Gauge thicknessSpeaker Connections Speaker TerminalsWhen to Set the Gain Control Knobs Above or Below Normal Gain Control Settings12V Position Automatic on/off Turn On OptionsManual Position Audio Position Automatic on/off12V Loop Out Jack AC Power CordVolt Jacks 12V In JackOn-Off Button Front Panel OperationBalanced and Unbalanced Lines Technically SpeakingGround Loops Eliminating Hum and Buzz Circuit Designed by John Curl Bare Speaker Wire EndsPower Supply Parasound a 31 Design OverviewInput Stage Complementary ConfigurationRelay-Bypassed Soft Start Circuit Audio Circuit Path TopologyTotal Protection Relays Output StageClass A-A/B Operation Total Protection DC ServosBackground Hum or Hiss Problems and RemediesUnit will not turn on No sound from speakersAre You Having Difficulty? Repair or ServiceSpecifications Parasound Products, Inc McKinnon Ave, San Francisco, CA