Today's Message Index:
----------------------
0. 12:52 AM - [Please Read] - Last Official Day of List Fund Raiser! (Matt Dralle)
1. 02:58 AM - Re: Radio noise (b d)
2. 07:43 AM - Re: iPod audio mix into headset line (James Robinson)
3. 07:53 AM - Re: Radio noise (Robert L. Nuckolls, III)
4. 10:25 AM - Re: Radio noise (Robert L. Nuckolls, III)
5. 10:42 AM - Re: iPod audio mix into headset line (Fisher Paul A.)
6. 11:18 AM - Re: iPod audio mix into headset line (Tim Olson)
7. 01:36 PM - Headphone impedance (Peter Pengilly)
8. 04:57 PM - Re: Radio noise (b d)
9. 05:12 PM - Re: Radio noise (Robert L. Nuckolls, III)
10. 06:21 PM - Re: Radio noise (Noel Loveys)
11. 06:46 PM - Re: Headphone impedance (Noel Loveys)
12. 07:06 PM - Re: Vans RPM Transducer IE VTACHGEN 12 (PhilCobbin)
13. 10:49 PM - Re: Headphone impedance (Ron Quillin)
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Subject: | [Please Read] - Last Official Day of List Fund Raiser! |
Dear Listers,
Its November 30th and that means at least two things. For better or worse, its
my 47th birthday! But it also means that its that last official day of the
Matronics Email List Fund Raiser! If you been drooling over one of the really
nice gifts that are available this year with a qualifying Contribution, then
now is the time to jump on one!!
If you've been meaning to make a Contribution this month but have been putting
it off for some reason, NOW is the time!
I will be posting the List of Contributors in a few days, so you'll probably want
to be known as a person that supported the Lists!
I want to thank everyone that has so generously made a Contribution this year in
support of our Lists. It is your generosity that keeps this operation running
and I don't ever forget it. Hopefully everyone feels the same.
The List Contribution Web Site is fast and easy. Please support our habit by making
your Contribution right now:
http://www.matronics.com/contribution
Or, by dropping a personal check in the mail to:
Matt Dralle / Matronics
581 Jeannie Way
Livermore CA 94550
Thank you to all in advance!
Matt Dralle
Matronics Email List Administrator
Message 1
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*Ron,*
**
*I'd say you agree with me, right Ron? I typically like to leave some
wiggle room for interpretation so I phrased my observation as a question as
opposed to a fact. Some people explain "parallel and series"
circuits differently than you and I do. You and I see and explain them the
same the correct way. I'm not trying to be petty or split hairs because it
really doesn't matter, I'm only pointing out that I did address the
"parallel and series" issue earlier. See below.*
**
*Best regards, Bruce*
On Mon, Nov 29, 2010 at 6:04 PM, Ron Quillin <rjquillin@cox.net> wrote:
> At 08:47 11/29/2010, you wrote:
>
> Saw a wiring diagram for another radio which stated that you must install a
> 22,000uf capacitor in series on the 12v feed when used with the Rotax engine
> installation.
>
>
> As no one else commented on what seems to be a typo or misunderstanding of
> terms...
> That capacitor would be parallel; that is the positive terminal to your
> buss, and the negative terminal to airframe or whatever you are using for a
> "ground".
>
*Bruce:*
*"In series or in parallel? Series doesn't sound right but then I don't
know if you are saying what I think you are saying. Series would not allow
any current to flow on a DC circuit hense the radio would not work. Parallel
would essentially filter out the unwanted noise sending it to ground."
(previous post)
*
>
> For a component to be in "series", the load current would flow through the
> component in series; clearly for DC and a capacitor, this would not work.
> Were it a coil, inductor, series would be the proper configuration.
>
> Ron Q.
>
>
> *
>
>
Message 2
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Subject: | Re: iPod audio mix into headset line |
Hi Tim
That is very interesting. I have been very happy with the Zulu's but I have not
done a direct comparison with the Bose. The Glasair without upholstery is very
noisy and the Zulu seem to work great, but I need to borrow someones Bose and do
a direct comparison. Good luck in your quest.
Jim
James Robinson
Glasair lll N79R
Spanish Fork UT U77
________________________________
From: Tim Olson <Tim@myrv10.com>
Sent: Mon, November 29, 2010 9:39:10 PM
Subject: Re: AeroElectric-List: iPod audio mix into headset line
Actually, that's the sad thing. I have 5 Bose X's, and ordered
two Bose A20's to get the music input (wired only). Then I
decided that even though I know I love the Bose best, I better
re-visit Lightspeed Zulu's. These are for the kids, BTW, so
small heads for sure. Even myself, I wear them at their smallest
setting, since I'm a pea-brained guy.
Anyway, we had the kids try the Zulu's on. They were too big.
But, then I heard about the thicker head pad, and got
one on the way. I ordered a Zulu, and got it last week.
This weekend I got out for a test flight. That's where my
plans all fell apart. Up to that point, I was happy to just
buy 2 pairs of Zulu's for the kids, and be done with it.
The problem is, when I compared the Zulu's to my Bose X's,
which are supposed to be inferior to the A20's, I was very
very disappointed. The Zulu's were AWESOME for music
via bluetooth. I was thrilled with that. But, on the
ground I noticed one thing...the audio is higher
pitched more "tinny" on the Zulu's. Then, the real
disturbing thing...the in-flight test. On ground taxi,
the cabin noise was much louder, both the low rumble,
and the higher pitched rattles. In climbout, the Zulu's
were far noisier...in all respects. So much so that the
audio music took more volume just to hear it well. (that
said, the bluetooth volume can be made nice and loud)
But, they were very loud. In cruse...same thing. The
zulu's just didn't hold a candle to my Bose X's. I was
super upset, because I was hoping that the Zulu's would
dig me out of having to do all this work. If Bose would
have only come out with A2DP streaming music input in
the A20's I'd buy it in a heartbeat, but man, what a
stupid mistake they made by not doing it...a dedicated
guy with 5 pairs who'd gladly buy 2 more, and they don't
actually make a product that can compete in features?
The fit and clamping pressure is great with the Zulu's,
and I can get a bit better noise reduction if I hold
the earcups tightly on my head, but even if I ordered
their thicker earpads, that's not really a solution...even
with them held tight, they still weren't as quiet. In
fact, my wife thought the difference was so stark she
told me "OH, did you forget to power them on?!?!", and
sadly, I hadn't forgotten.
So yeah, the Zulu's would be a great solution, but having
actually ran them head-to-head, I can't sacrifice that
much on noise reduction and be happy. Even passive
noise reduction wasn't really much different than the X's.
I got the impression that when you read magazine reviews
on these headsets that it's either VERY VERY VERY perfect
fit oriented, or that the reviewers don't want to lose
advertising revenue, because I really didn't find them
to be nearly as equal as all the reviews would indicate.
I may call them tomorrow to see if there is anything that
can be tweaked to fix it. Had they fit like Bose,
and sounded like Bose, I'd have bought another pair
in a heartbeat and I wouldn't be asking for this circuit.
Tim Olson - RV-10 N104CD
do not archive
On 11/29/2010 9:58 PM, James Robinson wrote:
> Hi Tim
> it is to bad you didn't go with Lightspeed. They allow a IPod directly
> into the controler or by bluetooth I think. I plug my ipod nano directly
> into mine and it works great.
>
> Jim
> James Robinson
> Glasair lll N79R
> Spanish Fork UT U77
>
>
> ------------------------------------------------------------------------
> *From:* Tim Olson <Tim@myrv10.com>
> *To:* aeroelectric-list@matronics.com
> *Sent:* Mon, November 29, 2010 8:28:58 PM
> *Subject:* AeroElectric-List: iPod audio mix into headset line
>
> <mailto:Tim@myrv10.com>>
>
> I thought I'd ask for a bit of help on this mini-project I
> am going to try to tackle.
>
> My goal is to be able to take my standard Bose X headsets,
> and splice in at jack point in the rear seats, so that I
> can mix an ipod audio signal into the headset audio. Sounds
> pretty simple, but...
>
> With the impedance mismatch between the ipod (I think 32 or
> 36 ohms) and the headset (what is it, 300?) you would get only
> quiet audio. I checked by plugging the headset with an
> adapter directly into the ipod and it just was too quiet.
>
> I did a little digging into simple mixer circuits with
> 10K resistors only, to combine the audio, and I'm guessing
> that would work, if the ipod was just amp'd up a bit.
>
> One thing I am NOT concerned with, is auto-muting of
> music, or anything like that. This is for rear-seat
> only, for the kids. I want them to each be able
> to plug in their ipod into an armrest jack, and hear
> their own individual music in the headset. Right now,
> they can plug into the intercom's input #2, and get the
> SAME music, but I want them to have the option to
> get DIFFERENT music than the other. I do want it to be
> Stereo, too.
>
> So what I really am thinking I need to come up with is a
> simple amp/mixer circuit that would perhaps impedance
> match, or perhaps just amplify the ipod audio and then
> mix it in.
>
> To make it even more fun, once I get far enough that
> I know this works, I'm going to plug a bluetooth
> audio interface into that jack, and that way they can
> just pair their ipod touch with the bluetooth module
> and go wire-free.
>
> So does anyone have any good advice on the circuit to
> accomplish this? FWIW, I'd be
>
> *
>
> *
Message 3
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Saw a wiring diagram for another radio which stated that you must
install a 22,000uf capacitor in series on the 12v feed when used with
the Rotax engine installation.
Ron correctly replies:
As no one else commented on what seems to be a typo
or misunderstanding of terms... That capacitor would
be parallel; that is the positive terminal to your
buss, and the negative terminal to airframe or
whatever you are using for a "ground".
For a component to be in "series", the load current
would flow through the component in series; clearly
for DC and a capacitor, this would not work.
Were it a coil, inductor, series would be the
proper configuration.
Ron Q.
Some people explain "parallel and series" circuits differently
than you . . .
May I suggest that differences in explanation have
more to do with illuminating the speaker's understanding
than it does with debating the value of various
'interpretations'?
I'll refer the debaters to the Z-figures were there
are numerous examples of how the subject capacitor
is wired. I'll also cite every text I've ever
picked up wherein Ohms law, reactance, and measurement
of currents and voltages are explained in uniform and
explicit illustrations for series and parallel connections.
An exemplar figure from the texts I used at Great Lakes
Naval Training Schools:
Emacs!
This goes to the value of common understanding
of the words used in language. Without common understanding
the useful exchange of ideas and knowledge cannot take
place.
Bob . . .
Message 4
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----------------
On Mon, Nov 29, 2010 at 8:47 AM, Philip Smith <madriver42@gmail.com> wrote:
I know this has been discussed before but like to ask anyway. I
installed an old RST 360 com radio in my 701 panel and when I start
the "Rotax" it is very noisy. Seems to be a whine don't know whether
or not this is alternator or ignition. Saw a wiring diagram for
another radio which stated that you must install a 22,000uf capacitor
in series on the 12v feed when used with the Rotax engine
installation. Will this cure the problem? Your valued thoughts please.
----------------
At 11:17 AM 11/29/2010, you wrote:
G`morning Phil
I am having a similar problem with my Kitfox Vixen with a 912UL. My
radio is a new ICOM A210. I have installed one capacitor on the
output from the voltage regulator. This helped but the problem still
there but not where I would like it. None of my wiring is shielded
and I am wondering if this would help.
Shielding of wires never fixes a "whine".
By whine, I presume you're describing a
sort of musical pitch noise. Further, if
it rises and falls in pitch with engine RPM,
it's almost certainly CONDUCTED noise from
the alternator coming in on the +14V bus
-OR- or is being injected to a signal or
power pathway due to poor grounding practice.
Here's the problem with attempts to remotely
diagnose and/or suggest prophylactic measures.
The combinations of engine, radios, and
intercoms being discussed have been installed
many, many times before with no reported
problems. From this admittedly anecdotal
observation I deduce that something in the
problem-systems is DIFFERENT than for the
historical fleet of similar systems.
The 'street-wise' suggestions for fixing
the symptoms will include a sprinkling of
materials and processes known to have some
beneficial effects on some noise problem on
some system at some point in history. But
as described in the chapter on noise, every
noise problem has a (1) victim (obviously),
(2) a propagation pathway and a (3) source.
Deducing the noise-trinity is a lot like
playing the board game Clue. In the
cases before us now, we know (1) and (3).
The task is to deduce (2). Techniques
for filling in (2)____________ blank
are described in the chapter on noise.
Alternatively, one can ponder a constellation
of hypotheticals with some assurance that
EVENTUALLY the noise can be run to ground
or at least reduced to tolerable levels.
Bob . . .
Message 5
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Subject: | iPod audio mix into headset line |
Tim,
Is this what you are looking for? http://www.vx-aviation.com/page_2.html
I know you asked for a circuit, but I remember seeing these in the past. Never
used one though...
- Paul
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Tim Olson
Sent: Tuesday, November 30, 2010 00:30
Subject: Re: AeroElectric-List: iPod audio mix into headset line
...snip...
Message 6
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Subject: | Re: iPod audio mix into headset line |
Thanks Paul,
I did run across that last night. Almost emailed for more
info. My first thought is, it's probably MORE than I
need. I don't need Cell input, and I can't tell from
some of the descriptions on other models if it can
mix Stereo to my Stereo intercom, or only mix stereo into
Mono. With all of the features it may be just a little
higher on price than I'm looking for, although if it
worked perfectly and was clear to me how it would work
for my installation, and be airplane powered, I'd probably
consider it.
Right now, with the lack of any D-I-Y circuits
that look ideal, I'm considering this
Boostaroo Revolution:
http://www.boostaroo.com/store_detail.php4?id=114
which I at least know I can just power via 12V, so
it would amp the iPod signal easily.
Then, I can do a simple resistor-only circuit to
mix the audio to the headset audio. I did order
a couple of isolator cords from Crutchfield too,
to prevent ground loops and make headset whine.
So, I'm at the point where I know I can do the
bare minimum for about $60, or do Bluetooth
with all that for about $140 per seat in the rear.
I need one of my Bluetooth things to come in so I
can verify if I need an amp first.
Tim Olson - RV-10 N104CD
do not archive
On 11/30/2010 12:37 PM, Fisher Paul A. wrote:
> --> AeroElectric-List message posted by: "Fisher Paul A."<FisherPaulA@johndeere.com>
>
> Tim,
> Is this what you are looking for? http://www.vx-aviation.com/page_2.html
>
> I know you asked for a circuit, but I remember seeing these in the past. Never
used one though...
>
> - Paul
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Tim Olson
> Sent: Tuesday, November 30, 2010 00:30
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: iPod audio mix into headset line
>
> --> AeroElectric-List message posted by: Tim Olson<Tim@myrv10.com>
>
> ...snip...
>
Message 7
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Subject: | Headphone impedance |
Hi,
I have a question concerning headset impedance, and what will work. I am
trying to build a helmet for use in an aerobatic airplane, the principal
requirement is to be as thin as possible on top of my head. I have found
a parachuting helmet that seems ideal - and is very comfortable. Now I
want to add comms. I was going to use a Halo headset, but its a problem
sticking the ear plugs in your ears before putting the helmet on. At the
weekend I was at a motorcycle show and was talking with an intercom
maker. He sold me a kit to add comms to a motorcycle helmet, including
an electret boom mic and a pair of thin speakers that fix inside the
helmet. He didn't know the impedance of the speakers, but suspects they
are quite low. I said I needed 600 ohms - his reply was that it wouldn't
be a problem. The audio system is quite simple - Becker AR4201 straight
to the headset. The Becker manual says:
Receiver data ... Rated output: for speaker operation:
at 13.75 V nominal operating voltage >= 3 W at 4 ohms
at 10.0 V operating voltage (emergency mode) >= 1.5 W at 4 ohms
with headset connected:
at 13.75 V nominal operating voltage >= 100 mW at 600 ohms
at 10.0 V operating voltage (emergency mode) >= 30 mW at 600 ohms
So the question is, how are these speakers that I am about to stick into
my helmet going to react when the radio output is fed to them? If their
impedance is low I'm guessing that will impact the volume, so I imagine
I will have to turn the radio volume up? It a noisy airplane and is
already up fairly high. Can I add some resistors to help out? Do I
connect both speakers to the tels output (doesn't that cut the already
low impedance in half?) Are all electret mics the same?
Thanks, Peter
Message 8
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Okay, whatever! LOL
*"May I suggest that differences in explanation have*
*
more to do with illuminating the speaker's understanding
than it does with debating the value of various
'interpretations'?
I'll refer the debaters to the Z-figures were there
are numerous examples of how the subject capacitor
is wired. I'll also cite every text I've ever
picked up wherein Ohms law, reactance, and measurement
of currents and voltages are explained in uniform and
explicit illustrations for series and parallel connections.
An exemplar figure from the texts I used at Great Lakes
Naval Training Schools:
This goes to the value of common understanding of the words used in
language.
Without common understanding **the useful exchange of ideas and knowledge
cannot take place. *
*
**Bob . . ."*
Message 9
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At 06:51 PM 11/30/2010, you wrote:
>Okay, whatever! LOL
Read that wrong. My apologies . . .
Bob . . .
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Bob:
I feel a bit like I must have early onset Alzheimer's. I should have
noticed that the description was to wire the capacitor in series on a DC
circuit. As I'm sure you know but others may not, capacitors block DC and
pass AC. So if you have a problem with noise on a DC feed simply put a
capacitor from that line to ground and any noise (AC) on that line should be
shunted to ground assuming the capacitor is of adequate size.
Noel
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: November 30, 2010 12:20 PM
Subject: Re: AeroElectric-List: Radio noise
Saw a wiring diagram for another radio which stated that you must install a
22,000uf capacitor in series on the 12v feed when used with the Rotax engine
installation.
Ron correctly replies:
As no one else commented on what seems to be a typo
or misunderstanding of terms... That capacitor would
be parallel; that is the positive terminal to your
buss, and the negative terminal to airframe or
whatever you are using for a "ground".
For a component to be in "series", the load current
would flow through the component in series; clearly
for DC and a capacitor, this would not work.
Were it a coil, inductor, series would be the
proper configuration.
Ron Q.
Some people explain "parallel and series" circuits differently than you .
. .
May I suggest that differences in explanation have
more to do with illuminating the speaker's understanding
than it does with debating the value of various
'interpretations'?
I'll refer the debaters to the Z-figures were there
are numerous examples of how the subject capacitor
is wired. I'll also cite every text I've ever
picked up wherein Ohms law, reactance, and measurement
of currents and voltages are explained in uniform and
explicit illustrations for series and parallel connections.
An exemplar figure from the texts I used at Great Lakes
Naval Training Schools:
Emacs!
This goes to the value of common understanding
of the words used in language. Without common understanding
the useful exchange of
ideas and knowledge cannot take
place.
Bob . . .
Message 11
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Subject: | Headphone impedance |
Looks to me your receiver requires a 4 ohm impedance. BTW you have to be
careful not to confuse impedance with resistance even though they are
related. Most low impedance headphones are 4 Ohms but check it should be
written on the phones somewhere. A mismatch of impedance can result in poor
clarity and in some instances problems with the audio output transistors of
the radio.
Noel
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Peter
Pengilly
Sent: November 30, 2010 6:01 PM
Subject: AeroElectric-List: Headphone impedance
<peter@sportingaero.com>
Hi,
I have a question concerning headset impedance, and what will work. I am
trying to build a helmet for use in an aerobatic airplane, the principal
requirement is to be as thin as possible on top of my head. I have found
a parachuting helmet that seems ideal - and is very comfortable. Now I
want to add comms. I was going to use a Halo headset, but its a problem
sticking the ear plugs in your ears before putting the helmet on. At the
weekend I was at a motorcycle show and was talking with an intercom
maker. He sold me a kit to add comms to a motorcycle helmet, including
an electret boom mic and a pair of thin speakers that fix inside the
helmet. He didn't know the impedance of the speakers, but suspects they
are quite low. I said I needed 600 ohms - his reply was that it wouldn't
be a problem. The audio system is quite simple - Becker AR4201 straight
to the headset. The Becker manual says:
Receiver data ... Rated output: for speaker operation:
at 13.75 V nominal operating voltage >= 3 W at 4 ohms
at 10.0 V operating voltage (emergency mode) >= 1.5 W at 4 ohms
with headset connected:
at 13.75 V nominal operating voltage >= 100 mW at 600 ohms
at 10.0 V operating voltage (emergency mode) >= 30 mW at 600 ohms
So the question is, how are these speakers that I am about to stick into
my helmet going to react when the radio output is fed to them? If their
impedance is low I'm guessing that will impact the volume, so I imagine
I will have to turn the radio volume up? It a noisy airplane and is
already up fairly high. Can I add some resistors to help out? Do I
connect both speakers to the tels output (doesn't that cut the already
low impedance in half?) Are all electret mics the same?
Thanks, Peter
Message 12
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Subject: | Re: Vans RPM Transducer IE VTACHGEN 12 |
If you search around the Van's website there are installation notes on the various
guages they sell and a drawing showing how they are typically wired.
If you put say, 5 volts (instead of 12v) and slowly rotate the spindle on the sensor
you will see it generate 8 steps of 4.26 volts. If you hook it up to 12
volts, you'll get comparable results. Since the sensor is typically attached
to the camshaft, there are 4 steps from the unit per crankshaft revolution.
attached is a jpeg of a digital tach setup I'm breadboarding for my rv7 using the
little Italian arduino boards.
The van's gauge if you take it apart and peruse the circuit board you will find
it uses a frequency to voltage chip to drive the guage.
Sorry about the size of the jpeg...
Phil
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=321873#321873
Attachments:
http://forums.matronics.com//files/2010_11_30_rv7_dig_tach_02s_145.jpg
Message 13
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Subject: | Re: Headphone impedance |
At 13:31 11/30/2010, you wrote:
><peter@sportingaero.com>
>
>Hi,
>
>I have a question concerning headset impedance, and what will work.
>I am trying to build a helmet for use in an aerobatic airplane, the
>principal requirement is to be as thin as possible on top of my
>head. I have found a parachuting helmet that seems ideal - and is
>very comfortable. Now I want to add comms. I was going to use a Halo
>headset, but its a problem sticking the ear plugs in your ears
>before putting the helmet on. At the weekend I was at a motorcycle
>show and was talking with an intercom maker. He sold me a kit to add
>comms to a motorcycle helmet, including an electret boom mic and a
>pair of thin speakers that fix inside the helmet. He didn't know the
>impedance of the speakers, but suspects they are quite low. I said I
>needed 600 ohms - his reply was that it wouldn't be a problem. The
>audio system is quite simple - Becker AR4201 straight to the
>headset. The Becker manual says:
>Receiver data ... Rated output: for speaker operation:
>at 13.75 V nominal operating voltage >= 3 W at 4 ohms
>at 10.0 V operating voltage (emergency mode) >= 1.5 W at 4 ohms
>with headset connected:
>at 13.75 V nominal operating voltage >= 100 mW at 600 ohms
>at 10.0 V operating voltage (emergency mode) >= 30 mW at 600 ohms
From your post, it is unclear if you plan on connecting your helmet
speakers to the speaker output, or the headphone output. It would be
inappropriate to connect them to the HP output, as they would
excessively load the receiver if connected to an output designed to
feed a 600 ohm load.
Were you to connect them to the speaker output, loading would not be
an issue, but you may find level control to be difficult as the
speakers would be much closer to your ear than cabin mounted
transducer(s). Some series resistance would likely be helpful and
desired when connected to the speaker output, but used as helmet headphones.
Additionally, if the radio provides speaker muting during xmit, you
would have no 'sidetone'. Something else to consider.
>So the question is, how are these speakers that I am about to stick
>into my helmet going to react when the radio output is fed to them?
>If their impedance is low I'm guessing that will impact the volume,
>so I imagine I will have to turn the radio volume up? It a noisy
>airplane and is already up fairly high. Can I add some resistors to
>help out? Do I connect both speakers to the tels output (doesn't
>that cut the already low impedance in half?) Are all electret mics the same?
>
>Thanks, Peter
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