Today's Message Index:
----------------------
1. 02:11 AM - Headphone squeal (Jay Hyde)
2. 06:47 AM - Re: Headphone squeal (Charlie England)
3. 07:03 AM - Re: Headphone squeal (Ralph E. Capen)
4. 07:15 AM - Re: Headphone squeal ()
5. 07:35 AM - Re: Headphone squeal (Tim Andres)
6. 08:19 AM - Re: Headphone squeal (Jay Hyde)
7. 09:02 AM - parelling two rp3 indicators (Bill S)
8. 09:21 AM - Re: Headphone squeal (Dj Merrill)
9. 03:20 PM - Re: Headphone squeal (Jared Yates)
10. 04:23 PM - Re: parelling two rp3 indicators (Robert L. Nuckolls, III)
11. 05:53 PM - Gooseneck map light assy available . . . (Robert L. Nuckolls, III)
Message 1
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Subject: | Headphone squeal |
I'm busy trying to solve a problem of a load squeal in the headphones. The
installation was done by somebody else and I'm picking up the pieces J
The system uses a Flightcom 403 intercom and has pilot, copilot and 2 pax
places. I see that both the headphone and microphone wires are run in the
same shielded cable (a 3 core cable). Whenever you plug a headset into any
of the pax places you get an almost immediate squeal in all the 'phones.
Sometimes it does not start immediately, but as soon as you tap or try to
speak into the microphone the squeal starts. Best practice suggests that
the microphone and headphones wire should be separate and shielded so I
suspect that this may be where the problem lies.
Anybody else had similar problems?
Jay
Message 2
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Subject: | Re: Headphone squeal |
On 12/22/2011 04:07 AM, Jay Hyde wrote:
>
> I'm busy trying to solve a problem of a load squeal in the
> headphones. The installation was done by somebody else and I'm
> picking up the pieces J
>
> The system uses a Flightcom 403 intercom and has pilot, copilot and 2
> pax places. I see that both the headphone and microphone wires are
> run in the same shielded cable (a 3 core cable). Whenever you plug a
> headset into any of the pax places you get an almost immediate squeal
> in all the 'phones. Sometimes it does not start immediately, but as
> soon as you tap or try to speak into the microphone the squeal
> starts. Best practice suggests that the microphone and headphones
> wire should be separate and shielded so I suspect that this may be
> where the problem lies.
>
> Anybody else had similar problems?
>
> Jay
>
To eliminate the easy stuff first:
Are the all headphones on or off the heads of the users? If any headset
is plugged in but *not* properly installed on a head, you can get a
positive-feedback squeal as soon as you excite the system by speaking
into or tapping on a mic.
I wouldn't claim that it's impossible for the wire to cause the problem,
but look at the cable attached to the headphones. :-)
Charlie
Message 3
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Subject: | Re: Headphone squeal |
My copilot station pops and breaks squelch when there isn't a head between the
mic and earpieces. The noise from the vent or heater kicks it off so I unplug
the mic jack when I'm flying solo.....
Someone else mentioned something similar to this - so I'm chiming in too.....
-----Original Message-----
>From: Jay Hyde <jay@horriblehyde.com>
>Sent: Dec 22, 2011 5:07 AM
>To: aeroelectric-list@matronics.com
>Subject: AeroElectric-List: Headphone squeal
>
>I'm busy trying to solve a problem of a load squeal in the headphones. The
>installation was done by somebody else and I'm picking up the pieces J
>
>
>
>The system uses a Flightcom 403 intercom and has pilot, copilot and 2 pax
>places. I see that both the headphone and microphone wires are run in the
>same shielded cable (a 3 core cable). Whenever you plug a headset into any
>of the pax places you get an almost immediate squeal in all the 'phones.
>Sometimes it does not start immediately, but as soon as you tap or try to
>speak into the microphone the squeal starts. Best practice suggests that
>the microphone and headphones wire should be separate and shielded so I
>suspect that this may be where the problem lies.
>
>
>
>Anybody else had similar problems?
>
>
>
>Jay
>
Message 4
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Subject: | Re: Headphone squeal |
One 3-conductor shielded cable for both mic and phone? How are the
grounds (collar) for each plug isolated from each other as well as from
airframe ground?
I think you are barking up the right tree. If the system is not wired
as the intercom manufacturer suggests, that=99s the first place to
start.
-James
From: Charlie England
Sent: Thursday, December 22, 2011 8:43 AM
Subject: Re: AeroElectric-List: Headphone squeal
On 12/22/2011 04:07 AM, Jay Hyde wrote:
I=99m busy trying to solve a problem of a load squeal in the
headphones. The installation was done by somebody else and I=99m
picking up the pieces J
The system uses a Flightcom 403 intercom and has pilot, copilot and 2
pax places. I see that both the headphone and microphone wires are run
in the same shielded cable (a 3 core cable). Whenever you plug a
headset into any of the pax places you get an almost immediate squeal in
all the =98phones. Sometimes it does not start immediately, but
as soon as you tap or try to speak into the microphone the squeal
starts. Best practice suggests that the microphone and headphones wire
should be separate and shielded so I suspect that this may be where the
problem lies.
Anybody else had similar problems?
Jay
Message 5
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Subject: | Re: Headphone squeal |
On 12/22/2011 2:07 AM, Jay Hyde wrote:
>
> I'm busy trying to solve a problem of a load squeal in the
> headphones. The installation was done by somebody else and I'm
> picking up the pieces J
>
> The system uses a Flightcom 403 intercom and has pilot, copilot and 2
> pax places. I see that both the headphone and microphone wires are
> run in the same shielded cable (a 3 core cable). Whenever you plug a
> headset into any of the pax places you get an almost immediate squeal
> in all the 'phones. Sometimes it does not start immediately, but as
> soon as you tap or try to speak into the microphone the squeal
> starts. Best practice suggests that the microphone and headphones
> wire should be separate and shielded so I suspect that this may be
> where the problem lies.
>
> Anybody else had similar problems?
>
> Jay
>
> *
> *
Jay; from what I have read about this, putting mic & phone audio inside
the same shielded cable will almost guarantee what you are seeing. If
you go to PSE's site, ( http://www.ps-engineering.com/support.shtml )
they have a Power Point file on how to wire an audio panel. Lots of
other tips & tricks on the ppt also.
Tim
> *
> *
Message 6
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Subject: | Headphone squeal |
I received a response from Flightcom, "If a mono headset is plugged into the
intercom or a stereo headset that is set to mono, this will cause the
squeal. Or if the wiring is not shielded cable, and the mic and headphone
wires are in the same cable"
So it seems that I am barking up the right tree (at least in terms of the
wires- not sure that I get the mono/ stereo thing, especially since their
system is mono.) , which is what I thought; but thanks for the inputs. I am
going to re-wire the system and will give you feedback when done.
Jay
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Tim
Andres
Sent: 22 December 2011 05:33 PM
Subject: Re: AeroElectric-List: Headphone squeal
On 12/22/2011 2:07 AM, Jay Hyde wrote:
I'm busy trying to solve a problem of a load squeal in the headphones. The
installation was done by somebody else and I'm picking up the pieces J
The system uses a Flightcom 403 intercom and has pilot, copilot and 2 pax
places. I see that both the headphone and microphone wires are run in the
same shielded cable (a 3 core cable). Whenever you plug a headset into any
of the pax places you get an almost immediate squeal in all the 'phones.
Sometimes it does not start immediately, but as soon as you tap or try to
speak into the microphone the squeal starts. Best practice suggests that
the microphone and headphones wire should be separate and shielded so I
suspect that this may be where the problem lies.
Anybody else had similar problems?
Jay
Jay; from what I have read about this, putting mic & phone audio inside the
same shielded cable will almost guarantee what you are seeing. If you go to
PSE's site, ( http://www.ps-engineering.com/support.shtml )
they have a Power Point file on how to wire an audio panel. Lots of other
tips & tricks on the ppt also.
Tim
Message 7
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Subject: | parelling two rp3 indicators |
I am wanting to parllel two Ray Allen RP3 led position indicators useing
only one POS5 position sensor. RAC said that thay wont work just
parelling them and that I need to add another position sensor or a
switch which I would rather not do. Can anyone sudjest an electrical
ckt. that would work for this? Thanks Bill S.
Message 8
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Subject: | Re: Headphone squeal |
On 12/22/2011 11:16 AM, Jay Hyde wrote:
> Or if the wiring is not shielded cable, and the mic and
> headphone wires are in the same cable
I'm a bit confused by this. Aren't the mic and headphone wires in the
same cable on the headphone itself (ie, the cable that goes between the
headphone and the plugs)?
-Dj
Message 9
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Subject: | Re: Headphone squeal |
I would suggest barking up the mono/stereo tree. I have installed this inter
com and I added a stereo/mono switch at each station, per the directions. I c
an send you a pdf of the install manual if you need it. I can produce a sque
al in my system by operating that switch incorrectly.
On Dec 22, 2011, at 11:16, "Jay Hyde" <jay@horriblehyde.com> wrote:
> I received a response from Flightcom, =9CIf a mono headset is plugge
d into the intercom or a stereo headset that is set to mono, this will cause
the squeal. Or if the wiring is not shielded cable, and the mic and headpho
ne wires are in the same cable=9D
>
> So it seems that I am barking up the right tree (at least in terms of the w
ires- not sure that I get the mono/ stereo thing, especially since their sys
tem is mono) , which is what I thought; but thanks for the inputs.
I am going to re-wire the system and will give you feedback when done.
>
> Jay
> From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelect
ric-list-server@matronics.com] On Behalf Of Tim Andres
> Sent: 22 December 2011 05:33 PM
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Headphone squeal
>
> On 12/22/2011 2:07 AM, Jay Hyde wrote:
> I=99m busy trying to solve a problem of a load squeal in the headpho
nes. The installation was done by somebody else and I=99m picking up t
he pieces J
>
> The system uses a Flightcom 403 intercom and has pilot, copilot and 2 pax p
laces. I see that both the headphone and microphone wires are run in the sa
me shielded cable (a 3 core cable). Whenever you plug a headset into any of
the pax places you get an almost immediate squeal in all the =98phone
s. Sometimes it does not start immediately, but as soon as you tap or try t
o speak into the microphone the squeal starts. Best practice suggests that t
he microphone and headphones wire should be separate and shielded so I suspe
ct that this may be where the problem lies.
>
> Anybody else had similar problems?
>
> Jay
>
>
> Jay; from what I have read about this, putting mic & phone audio inside th
e same shielded cable will almost guarantee what you are seeing. If you go t
o PSE's site, ( http://www.ps-engineering.com/support.shtml )
> they have a Power Point file on how to wire an audio panel. Lots of other t
ips & tricks on the ppt also.
> Tim
>
>
>
> -- Please Support Your Lists This Month nbsp; (And Get Some AWE
SOME FREE November is the Annual List Fund Raiser. Click below to find o
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ilities such as List Photoshare, and much much --> http://www.matronics.c
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>
>
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Message 10
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Subject: | Re: parelling two rp3 indicators |
At 10:59 AM 12/22/2011, you wrote:
>I am wanting to parllel two Ray Allen RP3 led position indicators
>useing only one POS5 position sensor. RAC said that thay wont work
>just parelling them and that I need to add another position sensor
>or a switch which I would rather not do. Can anyone sudjest an
>electrical ckt. that would work for this? Thanks Bill S.
>
You need a 'buffer-amplifier' between the position
feedback potentiometer and ONE of the two indicators.
The problem with paralleling the two indicators arises
from the fact that they're not a 'high impedance' voltmeter.
The system is calibrated for one pot driving one indicator.
Adding a second indicator doubles the load on the position
signal from the potentiometer.
The 'fix' is to convert one of the indicators into a
high-impedance voltmeter. You need an operational
amplifier with rail-to-rail inputs and outputs. A device
like the LM7321 would probably work.
http://search.digikey.com/us/en/products/LM7321MF%2FNOPB/LM7321MFCT-ND/1878646
Adding this device to the second indicator prevents
it from loading the potentiometer. You need to
fabricate something like this . . .
http://aeroelectric.com/Pictures/Schematics/Ray-Allen_Dual_Indicators.pdf
It could be fabricated on an etched circuit board
that would fit inside a d-sub connector back shell.
Bob . . .
Message 11
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Subject: | Gooseneck map light assy available . . . |
I was sorting out the contents of some moving
boxes and ran across this map light that used to
be on our website catalog.
http://aeroelectric.com/Pictures/Lighting/Map_LightA.JPG
http://aeroelectric.com/Pictures/Lighting/Map_LightB.JPG
Since I'm not building an airplane, I thought I would
offer this to any interested builder. You can get a mating
connection from Radio Shack
http://www.radioshack.com/product/index.jsp?productId=2103444
I also have a miniature Cessna style dimming rheostat to
go with it.
Emacs!
This is the same switch/dimmer used in the single-lamp,
overhead flood in single engine Cessnas.
Interested builders email me direct.
Bob . . .
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