Taildrgr

Taildrgr

Well Known Member
Most people reading this post will think this is very obvious to them, but I hope posting this will help someone like myself learn something they did not know.

I am working on my panel installation and recently purchased my headphone and mic jacks.

I had read on the forums about the need to insulate the jacks when mounting using fiber washers.

The jacks I purchased had fiber washers sandwiched in the layers of metal between the pins, and I thought that was what was being talked about. Also, the jacks came with the nuts and metal washers to mount them so I thought that they were ready to mount.

Lo and behold, I found out that I was supposed to order the fiber insulating washers separately! I did not know that. I assumed the jacks came with everything needed to install them.

You have to order two washers as shown below:

INSULATED FLAT WASHERS
Insulated flat washer for headset. microphone jacks. ACS P/N 04-00975

INSULATED SHOULDER WASHERS
Insulated shoulder washer for headset/ microphone jacks. ACS P/N 04-00976

I am glad I found this before I finished my installation as the shoulder washer required drilling a slightly larger mounting hole.

I am sure this has prevented many hours of troubleshooting noise issues later.
 
I think that the correct washers came with the jacks I ordered from Stein. Be sure to verify they are properly installed with an ohmmeter.

I don't use them in any case. I mount the jacks on a piece of 1/16" printed circuit board material and then mount it in the aircraft. In my -10, both the front and rear seat jacks are in the Aerosport center console. The P.C. Boards have nut plates so the console can be removed leaving the Jacks mounted to their boards.

I got the board material ( without copper) from Digikey. PC6-UNCLAD-ND
 
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I'm probably stating the obvious, but to help some of the newcomers......

For those using Aerosport Products carbon fiber products (or any other vendor's carbon fiber products), carbon conducts electricity. Be sure your jacks are isolated.

Get an ohm meter out during installation to validate that the jacks are isolated. I had one strand of carbon fiber that managed to get by the fiber insulators. This will save you many headaches later. Trying to find a ground loop after you have everything back in the plane is a royal PITA.

bob
 
Here is some help

I got this tip from the VAF site a few weeks ago so the credit needs to go to someone else. It saved me the problems described above.

Go to PS Engineering?s web site and on the support page there is a PowerPoint titled ?AudioSys Installations? under the ?Harness Building Training? paragraph. It was very helpful.

Good Luck
 
Stein Air !!

I got my headphone jacks and comm wiring from Stein. He included detailed instructions and jack wiring diagrams, including where the fiber washers go. Otherwise I was clueless.
 
As if you guys are in the shop with me!

Bob...you saved me some headaches! I just finished my jack installs in the Aerosport arm rest. The entire time, I thought about how I didn't need the fiber washers since I wasn't installing in the metal airframe. I totally forgot about the conductive nature of CF! I took my ohm meter out to the shop and sure enough, I need the washers.

Thanks again!
 
dhmoose said:
Bob...you saved me some headaches! I just finished my jack installs in the Aerosport arm rest. The entire time, I thought about how I didn't need the fiber washers since I wasn't installing in the metal airframe. I totally forgot about the conductive nature of CF! I took my ohm meter out to the shop and sure enough, I need the washers.

Thanks again!
Click to expand...

I'm glad my post was of assistance.

The other good news is that the composite material that the arm rest insert is made out doesn't conduct electricity.

The only issue I'm having is locating a source for a fiber washer with a 1/8" ID for my music jack. I may have to end up making one. Fortunately I've got until I finish Phase I before anyone needs music in the back seat.

Bob
 
Bob, you might have better luck with a teflon or nylon washer for your music jack. We have shoulder washers in both materials at my office, they're a standard off-the-shelf part from McMaster. They're also too small for this application, but I know they are available in many sizes...
 
Interestingly enough, while the mic and phone jacks all grounded to the composite of the arm rest, the music jack did not and I'm not sure why.
 
Snowflake said:
Bob, you might have better luck with a teflon or nylon washer for your music jack. We have shoulder washers in both materials at my office, they're a standard off-the-shelf part from McMaster. They're also too small for this application, but I know they are available in many sizes...
Click to expand...

duh...... I should have thought of that. I have a whole drawer of them at the hangar too.

Thanks,

Bob
 
Source for nylon shoulder washers?

Does anyone know a source for nylon (as contrasted with fiber) shoulder washers to insulate jacks? Spruce seems only to have fiber. Stein is the same. Digikey didn't seem to have the right size.

Thanks.
 
PS Engineering Power Point Presentation

Tumper said:
I got this tip from the VAF site a few weeks ago so the credit needs to go to someone else. It saved me the problems described above.

Go to PS Engineering?s web site and on the support page there is a PowerPoint titled ?AudioSys Installations? under the ?Harness Building Training? paragraph. It was very helpful.

Good Luck
Click to expand...

I thought I would take this opportunity to alert the Van?s Aircraft members that we no longer make this Power Point Presentation available. I would like to explain why we took it down in hopes that you ?all won?t hate me too much!

I just spoke with a person who purchased a PM3000 intercom and asked for the presentation. I honestly felt terrible when I told this customer that I would not send it to him. I did my level best to explain why in hopes that he wouldn?t be too upset, but I don?t know how well I did. It was a very difficult conversation for ME because I totally get it why pilots build airplanes; they want the satisfaction of building it themselves!

We have been building intercoms now for almost 30 years. I think we have a relatively good reputation for making good audio products for airplanes. And while the design and manufacturing of our products is very important, the installation is equally important to achieve the high performance of our audio systems.

Many years ago, we had a policy that for our warranty to be valid, a PS Engineering dealer had to perform the installation. Obviously, that did not go over well with our homebuilders. So about 15 years ago, we started to build custom harnesses for the homebuilder. That really helped us in the ?good guy? department.

Then we decided to create a Power Point presentation in hopes to provide some information on how to use solder sleeves and how to prep the wires and how proper shielded is achieved. Again, we had what we thought the best interest in for both parties.

Unfortunately for PS Engineering, what we thought would be a good thing for all parties, actually turned out to be a nightmare. Not only did the number of technical support phone regarding of building harnesses skyrocketed, we found ourselves being the ?culprit? for improper intercom functions because builders blamed our Power Presentation. Claims were made that since we produced this Power Point presentation, we were responsible for making their harness work!

So decided to remove the Power Point presentation about two years ago and stick with the availability of having either us or our dealers, build the harness. We have nothing against people building their own harness, that?s exactly what homebuilding is all about. We simply aren?t in a position to support those installations.

When we published the Power Point Presentation our hearts were in the right place, but unfortunately it created a completely unforeseen set of circumstances that we were not prepared to handle.

Thank you all for your trust in our intercoms and audio panels and I sure hope that this explanation why we no longer make this Power Point presentation available is understandable.
 
Mark,

Could you share your views on why not to use the shield as the current path for audio return? It's not clear to me what noise source would be exacerbated by doing so.

Thanks,
David
 
Both jacks?

Could someone please confirm BOTH the headphone and mic jacks need the fiber washers to insulate them from the airframe. Im wiring to a PS Engineering PAR100EX
Thank you
Bob
 
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bobmarkert said:
Could someone please confirm BOTH the headphone and mic jacks need the fiber washers to insulate them from the airframe. Im wiring to a PS Engineering PAR100EX
Thank you
Bob
Click to expand...

Yes. You only want a single path to ground and that should be the the back of the PSE intercom or the point that the intercom is connected to the aircraft ground.
 
cmgolden said:
Does anyone know a source for nylon (as contrasted with fiber) shoulder washers to insulate jacks? Spruce seems only to have fiber. Stein is the same. Digikey didn't seem to have the right size.

Thanks.
Click to expand...

The shoulder washers we have are black plastic composite (not just a pure fiber, they are actually flexible), the flat one is the hard/phenolic type. The "fiber washer set" description just comes from the trade name that is thrown around for commonality. FYI, (they are a "kit" of two pieces)....

Hope that helps.

Cheers,
Stein
 
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mscheuer said:
Faraday Shielding!
Click to expand...

A Faraday cage is just a metal box. In the ideal world no external electric fields can penetrate to anything inside the box. But external fields can cause currents to flow on the outside of the box.
So wires inside the shield braid are shielded from external fields. But a current can be induced in the braid itself. Real braids have a finite resistance, so a voltage drop happens. If you use the braid as your headphone return that stray voltage looks like a signal to the intercom.
 
rleffler said:
Yes. You only want a single path to ground and that should be the the back of the PSE intercom or the point that the intercom is connected to the aircraft ground.
Click to expand...

Back of the intercom is best. In the real world there are usually multiple ground paths between the intercom and the ground buss bar.
 
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