AA12S Series Compact Audio Controller Manual

SM69 Rev. 4.00

2.3.2Cautions

In all installations, use shielded cable exactly as shown and ground as indicated. Significant ground loop and noise problems may result from not following these guidelines.

The shielding and routing of the MIC and ICS TIE LINES used in the AA12S installation is very critical and poor performance of the aircraft audio system will result if these issues are not handled properly.

The operation of the VOX intercom can be severely degraded by the quality and type or mix of microphones used in the aircraft. If one user has a very 'hot' microphone, it will present more electrical signal to the VOX circuit and the VOX SQUELCH will have to be set to quiet this microphone. The other microphones may not be able to generate enough electrical energy to overcome this VOX SQUELCH setting, and will break up or not be heard at all.

2.3.3Notes

Audio performance can be impaired by the introduction of airframe electrical noise at the headset jack locations. For best results, all headset jacks should be fully isolated from the airframe.

2.3.4Cabling and Wiring

All unshielded wire should be MIL-W-22759 or equivalent. For shielded wire applications, use Tefzel MIL-C-27500 shielded wire with solder sleeves (for shield terminations) to make the most compact and easily terminated interconnect. Follow the wiring diagrams in Section 2.6 as required.

Allow 3 inches from the end of the wire to the shield termination to allow the hood to be easily installed. Note that the hood is a ‘clamshell’ hood, and is installed after the wiring is complete.

All wiring should be at least 22 AWG, except power and ground lines, which should be at least 20 AWG. Ensure that all ground connections are clean and well secured.

2.3.5Post-Installation Checks

If any preset requires adjustment, be sure this is carried out before the aircraft leaves, and that the unit and its mating connector are secured before departure. Make all required log book entries, electrical load, weight and balance amendments and other paperwork as required by your local regulatory agency.

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Oct 13, 2005

ENG-FORM: 805-0106.DOT

 

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