Apr 09 2010

Headset Bushings

Today was a short day.  I had to make some mod’s on the laminater (for lettering) per Tech Support of Pulsar.  It should work a little better now.   

I made the new passenger comm panel (the original was sized wrong).    I checked the panel’s resistance (made of carbon fiber) and sure enough, it is VERY conductive which is a problem for the audio system.  Since the headset jacks are grounded, it means there is a real possibly of a ground loop from the mic to the headset ground via the carbon.  

This is the same issue which plauges an alum plane.  Many pilots find there is a bit of noise (whine, strobes, etc) in their headset caused by ground loops.     As owners started upgrading to carbon and aluminum panels few pay attention to the ground loop issue and are surprised to find their new system has more noise than their old setup.   The owner did not take into account the jacks which were mounted in electrically isolating fiberglass, now are mounted in carbon or alum and are creating a ground loop and noise.

In order to prevent comm noise,  a bushing and washer was machined out of delron to electrically isolate the mic and headset jacks from the carbon to eliminate the ground loop.

The new panel and bushings.   I’ll letter it tomorrow.  Now that I know what I am doing with the lettering kit, it should only take 20 min or so.

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