Parasound A 31 manual Turn On Options, Manual Position, Audio Position Automatic on/off

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Turn On Options

For convenience, there are three ways the A 31 can be turned on and off:

Manually, by pressing the On-Off (Power) button on the front panel.

Automatically, when an audio signal is present at any of the audio Input jacks.

Automatically, when a suitable trigger voltage is applied to the 12V input jack.

Note: When either automatic turn on option is selected the front panel On-Off button is disabled so that power on/off is determined solely by the triggering preamp, receiver or active audio signal.

Manual Position

When the Turn On Options switch is in its Manual position, the Turn On Options function is disabled and the A 31 must be turned on and off manually by pressing the On-Off button on its front panel every time you wish to use your audio system.

Audio Position (Automatic on/off)

When the Turn On Options switch is set to its Audio position, the A 31 will be turned on only when an audio signal is present at any of the Input jacks. After the audio signals cease the A 31 will remain on for about 8 minutes before shutting off. This prevents unintended turn-off during pauses in your music or movies.

Note: The Audio position of the Turn On Options switch disables the front panel On-Off button.

Turn On Threshold

This knob sets the audio signal level required for the A 31 to automatically turn on when the Turn On switch is set to the Audio position. Fully counter-clockwise is the most sensitive setting and therefore is labeled “Quieter.” Fully clockwise will require a higher audio signal voltage and is therefore labeled “Louder.” In most systems the best results will be with the Turn On Threshold knob set towards the Quieter position. In some systems the A 31 might turn on if there is transient noise in the AC line, even when an audio signal is not present. Similarly, the A 31 might never shut off even after waiting more than 10 minutes. In this case, try setting the knob towards the Louder position.

Note: When the Turn On Options switch is set to Audio the A 31 will turn itself on immediately when you connect its AC cord, even without any audio signal present. This is normal.

Note: If the A 31 is driving only the sub(s), surround, center, or rear channels you will achieve more consistent automatic turn on by using the 12V DC trigger. At the beginning of most films the sub, center and surround levels are lower than the minimum level required by the Audio sensing circuit.

12V Position (Automatic on/off)

When the Turn On Options switch is set to its 12V position, the A 31 is turned on and off only with an external +9 V to + 12 V voltage from your preamp or AV Receiver. When the external voltage ceases the A 31 will turn off immediately. The 12V switch position disables the front panel On-Off button.

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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 Connections Audio Input ConnectionsSpeaker Terminals Speaker Wire Length and Gauge thicknessSpeaker Connections Correct Speaker Polarity is ImportantGain Control Settings When to Set the Gain Control Knobs Above or Below NormalAudio Position Automatic on/off Turn On OptionsManual Position 12V Position Automatic on/off12V In Jack AC Power CordVolt Jacks 12V Loop Out JackFront Panel Operation On-Off ButtonBalanced and Unbalanced Lines Technically SpeakingGround Loops Eliminating Hum and Buzz Parasound a 31 Design Overview Bare Speaker Wire EndsPower Supply Circuit Designed by John CurlAudio Circuit Path Topology Complementary ConfigurationRelay-Bypassed Soft Start Circuit Input StageTotal Protection DC Servos Output StageClass A-A/B Operation Total Protection RelaysNo sound from speakers Problems and RemediesUnit will not turn on Background Hum or HissRepair or Service Are You Having Difficulty?Specifications Parasound Products, Inc McKinnon Ave, San Francisco, CA