Isolated audio jacks?

It says in the installation instructions for Dynon intercom SV-INTERCOM-25 that the audio jacks should be isolated from the panel. Is that something specific to Dynons intercomms or does it apply to all intercoms? I have a PM501, is it recommended to do the same with this one? I have installed the audio jacks on an aluminum bracket which will be riveted to the inside of the fuselage. Is that OK or not?

Yes.

As long as you install as indicated in your diagram using the nylon spacer and washer on both sides you will be ok.

You need to do that so you won't get a ground loop. Which would cause interference if you don't use them.

I mounted mine on a bracket like you described and used those insulators and I no interference.

Hans,

This is NOT unique to Dynon intercomms, and is common in most, if not all, mic and headphone jack installations.

In fact, PS Engineering recommends the same in their PM501 installation manual... "It is crucial that you use insulating washers on all microphone and headphone jacks to isolate the audio signal ground from the aircraft ground."

+1 what John said. All intercoms are like this. Drill your panel hole to fit the spacer, which keeps the jack from touching the panel. Most of the jacks I've seen have a fiber washer for the flat one. Also, remember that fiberglass and especially carbon fiber can be conductive, so you should isolate your jacks from those, too. Finally, usually you will use two or three conductor shielded cable (two conductors for mic jacks that won't be keyed - no PTT - or mono phone jacks; three for stereo phone jacks and keyed mic jacks). The shield is grounded at the intercom and floats at the jack end. Do not ground your shields to common ground.

I talked to a guy today and he said the same thing - always insulate audio jacks. I didn't know. How could I have missed that?

Thanks.