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MP/3 Pre-Amp Solution Needed

f1rocket

f1rocket

Well Known Member
I've got to figure that someone out there has solved this. I'm looking for a pre-amp for my MP/3 player so I can connect it to the audio input jack of my intercom system. I've searched and searched and cannot find a solution with the following characteristics:

1) Plug and play. I don't want a kit, circuit board, or jr. electronics project;
2) 12 VDC power, no battery;

You'd think this is a simple device to find, but I swear one doesn't exist. If someone has a lead on one, I'd be forever greatful. I found a snap-on-th-back power pack for the iPod that fits the criteria, but I don't have an iPod. I'm thinking it might work for my player but don't know what size jacks it uses.

Any help out there?
 
sonex293 said:
Are you going from a headphone jack or line out jack?

If your coming out of the headphone jack this might work...

http://surplusgizmos.zoovy.com/c=Adhv3gkJXpTKHmCsJ46dZs9Hh/product/AMP-1

Never heard of the company however.

--Michael
Click to expand...
Thanks Michael. The signal out of the MP/3 player needs to be boosted prior to entering the Audio Input signal of the intercom. This device looks interesting but I don't know if a 3 AMP boost is enough power. Does anyone know the answer to this?
 
Something I'll probably have to worry about when I start wiring up my Flightcom 403 intercom! Oh yea, I noticed it's a mono amplifier, so you'd need 2 for stereo. Might be other Headphone Amps out there.

--Michael
 
Randy, What Audio Panel are you using and what kind of MP3 Player? I've always used my iPod by just plugging the headphone output into the Music input. I'd thought that was actually the signal level that the audio panel was looking for. It always worked great in the old hawk I used to fly alot. It had a PS engineering panel. I did have to plug my iPod into the cigarette lighter to get it to put out more voltage on the output though. At any rate let me know what the specs are and I'll see what I can think of. Audio is right up my alley, I've been dealing with it for a long time. (of course massive rock concerts and 84k seat football stadiums are a bit different but the basics are the same.)

Jeff
 
I had the same dilema and after much searching settled for a kit amplifier. It can work on a 9v battery or use the aircraft power. I know this is not what you want but it does work well and is better than nothing. Of course the ipod is the real answer.
 
I think I finally found my problem. My "new" intercom I bought last year was actually discontinued in 1998 by PS Engineering. I have a PM2000 and it was discontinued because it lacked a pre-amp circuit for hand held music devices! Go figure. The new PM3000 replaces it and has said circuit.

So now, I either have to buy a PM3000 or buy a pre-amp.

Anyone in the market for a good used intercom??
 
Hello,

I am the owner of surplusgizmos and saw the thread.

I thought I would throw out a couple of thoughts.

First off my AMP-3 product will more than likely NOT work for what you wish to do. It is a MONO power amplifier that outputs aproximatly 3watts of power. It is designed to drive a speaker load of around 4 to 8ohms.
(the STI TDA2003 IC in the unit can actualy drive up to 10watts of audio power into a 8 ohm load)

If you run this into your input it will more than likely damage the input of your intercom if not other parts...
The other problem is that since it is mono it shorts the stereo output of your mp3 player and drives the input of the amp-3.
Many MP3 players will have no problem with this but some may.
Something to think about.

Now as to what will work...
That is a tougher question.

Basicly what is the input options on your intercom? Is it headphone 3.5mm or .25in?
What sort of input signal is it looking for 1mv peak to peak (which is line inputs) or pre-amp signal which varies as to the voltage levels.

Also more than likely your intercom is mono audio even if it drives two speakers. (I will ask my friend who flys and also check my intercom headsets I have sitting somewhere in my warehouse... hmm...)

If you have electronics experiance you could build a preamp with a quad op-amp chip (feed the stereo signal into two seperate op-amps channels and then feed this output to the third to boost the signal.)
The electronics needed will depend on what the input is on your system...

Of course you could always ask the manufacturer if they have an add-on that you can buy that will do what you want which you may have allready done.

I hope this rambling helps some.
If you have more details I might be able to give more feedback.

Take care,

Mike <><
http://www.SurplusGizmos.com
 
Thanks Mike,

Both the headphones and the intercom are stereo. It has a .25 music input plug. The manufacturer actually recommend "The MUSE" as a pre-amp. I don't like the fact that it uses a 9-volt battery and only gives you 15-20 hours of amp time. I'd rather have one that I can wire into 12 VDC.

I bought a pre-amp kit from Cankit (sp?) that I might try and wire up.

I figured this whole thing was more complicated that I thought, otherwise, there'd be a plug-and-play device out there to buy.
 
Try wal-mart

Wal-mart sells an impedance matching gadget in their automotive stereo department that says it will match a floating ground system (like car stereo speakers) to a common ground system (like an intercom). It's about $15. It has a gain adjustment for each of four channels, which I guess implies that it includes a pre-amp.

I don't know if it will solve your problem, but what the heck -- it's Wal-Mart -- you can always take it back. I bought one to solve my Sony stereo to Garmin audio panel problem, but haven't gotten around to installing it yet. (Too hot at the hangar. Man, I've become a wimp since I finished the plane!)
 
Hi F1rocket,

If the 9volt amp will work it is very simple to convert it to work with 12volts.

You use a voltage regulator to convert the higher voltage to the lower.
Here is a web page that explains them:
http://www.geocities.com/SiliconValley/2072/3pinvolt.htm

Be carefull about how much current you are going to draw as many regulators will require heatsinks if the current draw is high.

The regulator you need is a 7809 which is a 9volt.
You can search for one on www.digikey.com (electronic parts place) and will probably want one that is a to-220 package.
The only other parts you may need is possibly a capacitor and a small heatsink. You could solder it all together without a board if you insulate the wires from each other realy good.

Actualy now that I think about it you may not want to solder the parts together so another option is to get a car adaptor for a cdplayer.
This is the easiest method as these units will have a cigarete jack on one end and power plug on the other end.
You should be able to get one at just about any store that sells stereo equipment or even radio shack.
It will definatly make it more plug and play like you want... :)

I did a google search and came up with this product:
http://www.powerstream.com/dc6.htm
Check you local stores first as if something doesn't work right you don't want to have to try and mail something back.

Let me know if you have more questions or need help.

Take care,

Mike <><
http://www.SurplusGizmos.com
503-439-1249
 
I know next to nothing about electronics, but you might check out music stores. They make some really small little pocket amps that you can plug an electric guitar into and play through headphones. I used to have one that plugged into a cig lighter.

Steve Zicree
 
MP3 Pre-amp

I suggest posting your problem on the AeroElectric Matronics list - or at least doing a search. Lots of knowledgeable folks to help there.

You can wire the Muse pre-amp to your aircraft - just figure out the amperage draw and put the appropriate resistor in-line to drop the voltage. Or, check with the manufacturer - you may be able to hook it to 12V directly.

Dennis Glaeser
7A Wings
 
Thanks Dennis. I DID post this question to the Aerolectric list about 7 months ago. All I got back was a bunch of electronic gobbledigook that only an EE could understand. When I asked for a simple plug-and-play solution, I was chastised as "not wanting to learn more about how electrons work".

Well no, I don't want to learn more. I have enough to learn just to keep my job and keep my airplane flying. I don't want an EE minor degree in the process.

Thanks for the suggestion though. Re-wiring the MUSE might be a solution as well. I was hoping to not get too complicated a solution, but I'm guessing I'm going to need to wire up some contraption to get what I need. Or maybe I'll just spring for a new intercomm.
 
tommylewis said:
check out this product

http://www.boostaroo.com/

for boosting the sound from an mp3 player

Tom lewis
Click to expand...
I bought one of these because I thought I'd just take the simple way out. WRONG. The darn thing didn't do a thing. Still can't hear the music.

I talked to PS Engineering again. This time, they told me that there's a change an avionics shop can make to the intercom to correct the problem. So I plan to remove the intercom and drop it off at the shop this week. We'll see if that fixes things.

Man, this shouldn't be that tough. I should have bought an audio panel instead.
 
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