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  #61  
Old 07-24-2008, 08:54 AM
paulojess paulojess is offline
 
Join Date: Jan 2005
Location: Arizona
Posts: 10
Default

Thanks Canadian Joy, I have not heard much about an impedance mismatch problem with these "homemade" headsets.. I thought I was worrying about nothing!! ( I have most of the parts to start assemblying) I have not seen these transformers ... I'll have to look at Radio Shack online.....

Thanks again for the info..
Paulo
Finish Kit/ RV9A
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  #62  
Old 08-21-2008, 10:45 AM
jaco523 jaco523 is offline
 
Join Date: Aug 2008
Location: michigan
Posts: 1
Default impedance mismatch

Quote:
Originally Posted by Canadian_JOY View Post
Paulo - headset impedance is quite important - low impedance will overstress the audio amplifier in the intercom. The easiest fix for this is to put a small box in-line with the headset wires and install an audio impedance matching transformer. The transformer is pretty small (can be sourced through Mouser or similar suppliers, including Radio Shack, for very little money, under $10) and can be found with a 600 ohm input to match the output of the intercom, with an output of 16 ohms to match the little Comply or similar in-ear transducers. If one of these is installed in the "homemade" headset you'll find it works quite well.
Interesting, I was wondering about the impedance mismatch between aviation headsets and consumer headphones. Doesn't the inline volume control modify the impedance of the headphones?

Is anyone else using an audio transformer in their setup, or is everyone running a risk of damaging their intercoms?

has anyone else had success with their homemade headset and a garmin 340?

this is a great project, thanks to all who have contributed!
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  #63  
Old 10-18-2008, 07:15 AM
mojo6911 mojo6911 is offline
 
Join Date: Oct 2008
Location: Arlington, TX
Posts: 12
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Hey guys. I am a full time flight instructor, and the old DCs hurt my head when I fly 3-5 flights a day. I wanted something lightweight, but didn't have the extra $500 laying around.

I have a couple of quick questions:

1. Bluetooth interface: Anyone try to put a bluetooth into the system for cell phone use? I have an old in ear bluetooth adapter that I plan on hacking up and throwing in the project box. Obviously, I will have to relocate the ports and buttons and solder the speaker connection to the headphones.

2. Any way something like this could be used:



http://www.plantronics.com/north_ame...0032/audio-450

I would rather not have the behind the head wire. Could you simply put adapters on the 3.5mm plugs to interface with the standard aviation headset plugs?

Thanks!
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  #64  
Old 10-18-2008, 11:26 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,884
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I tried to find a spec sheet on the web site but couldn't. However, I did see the model 480, that looks better suited to a/c use. The earbuds are sound isolating & the mic boom is longer so you can get it in front of your lips.

Charlie
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  #65  
Old 10-19-2008, 04:06 PM
mojo6911 mojo6911 is offline
 
Join Date: Oct 2008
Location: Arlington, TX
Posts: 12
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Quote:
Originally Posted by rv7charlie View Post
I tried to find a spec sheet on the web site but couldn't. However, I did see the model 480, that looks better suited to a/c use. The earbuds are sound isolating & the mic boom is longer so you can get it in front of your lips.

Charlie

Thanks! I will let you guys know how the bluetooth adapter works.
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  #66  
Old 10-22-2008, 11:37 AM
Epsound Epsound is offline
 
Join Date: Sep 2008
Location: Colorado Springs
Posts: 214
Default Plantronics 480

These look nice. I couldn't find what they calculate the noise reduction to be. I wonder if these would be good enough as is? Also, how effective the noise cancelling mic would be in a 7A.

Last edited by Epsound : 10-22-2008 at 11:39 AM.
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  #67  
Old 10-23-2008, 04:52 PM
mrj22 mrj22 is offline
 
Join Date: Feb 2006
Location: South St. Paul MN
Posts: 38
Default Connecting Mic

I am in the process of building one of these headsets, but have a few questions. For those that used the ACS mic how did you connect the wires to the mic? Did you use some sort of pin soldered to the wire and then inserted into the mic?

Thanks for any help you can offer.

Mark
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  #68  
Old 10-27-2008, 05:35 PM
s_tones s_tones is offline
 
Join Date: Jan 2005
Posts: 114
Default headset hat

Taking the lead of others here....
I modified my favorite hat with a flexible boom (intubating stylet).
I bought that $20 A.Spruce mic and used a cell phone adapter that I had laying around as the junction box. Had only to add a 1/8" receptacle for the mic jack which I wired in tandem with the existing jack. Waiting for the Comply phones.




Steve
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  #69  
Old 11-20-2008, 07:28 PM
Jeff Boatright Jeff Boatright is offline
 
Join Date: Nov 2008
Location: Decatur, GA
Posts: 9
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Quote:
Originally Posted by jaco523 View Post
Interesting, I was wondering about the impedance mismatch between aviation headsets and consumer headphones. Doesn't the inline volume control modify the impedance of the headphones?

Is anyone else using an audio transformer in their setup, or is everyone running a risk of damaging their intercoms?

has anyone else had success with their homemade headset and a garmin 340?

this is a great project, thanks to all who have contributed!
Did you ever get a response about people using their homemade headsets without impedance-matching transformers? Has anyone found that this damages their intercoms?

Thanks in advance,

Jeff
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  #70  
Old 11-21-2008, 01:15 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,884
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I checked ebay for the plantronics 480s & found some for $10/set (mute button doesn't work; I don't care). I haven't had a chance to fly with them yet, but they seem well made. I doubt that the noise blocking will be as good as the high-dollar ones, but I'm betting they will be at least as good as my old Lightspeed 15xl's. The mic boom design is really not bad at all; a little tab fits in your outer ear to stabilize the mic angle instead of the over-the-ear design of most others.

Charlie
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