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  #11  
Old 08-07-2014, 09:21 AM
cmgolden cmgolden is offline
 
Join Date: Apr 2014
Location: Wichita, KS
Posts: 8
Default 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.
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  #12  
Old 08-07-2014, 11:24 AM
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mscheuer mscheuer is offline
 
Join Date: Oct 2005
Posts: 182
Default PS Engineering Power Point Presentation

Quote:
Originally Posted by Tumper View Post
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
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.
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  #13  
Old 08-07-2014, 11:34 AM
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digidocs digidocs is offline
 
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Default

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
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  #14  
Old 08-07-2014, 11:37 AM
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mscheuer mscheuer is offline
 
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Default

Quote:
Originally Posted by digidocs View Post
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
Faraday Shielding!
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PS Engineering, Inc.
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  #15  
Old 09-02-2014, 05:32 AM
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bobmarkert bobmarkert is offline
 
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Location: Littleton, CO
Posts: 388
Default 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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Last edited by bobmarkert : 09-02-2014 at 05:44 AM.
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  #16  
Old 09-02-2014, 06:21 AM
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rleffler rleffler is offline
 
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Location: Delaware, OH (KDLZ)
Posts: 4,196
Default

Quote:
Originally Posted by bobmarkert View Post
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
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.
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  #17  
Old 09-02-2014, 10:24 AM
SteinAir SteinAir is offline
 
Join Date: Feb 2005
Location: Minneapolis
Posts: 2,473
Default

Quote:
Originally Posted by cmgolden View Post
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.
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

Last edited by SteinAir : 09-03-2014 at 06:02 PM.
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  #18  
Old 09-02-2014, 12:00 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 6,797
Default

Quote:
Originally Posted by mscheuer View Post
Faraday Shielding!
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.
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  #19  
Old 09-02-2014, 12:07 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 6,797
Default

Quote:
Originally Posted by rleffler View Post
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.
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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