MP/3 Pre-Amp Solution Needed

[f1rocket]

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]

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=Adh.../product/AMP-1

Never heard of the company however.

--Michael

[f1rocket]

Originally Posted by sonex293

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=Adh.../product/AMP-1

Never heard of the company however.

--Michael

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?

[sonex293]

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

[1911pilot]

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

[rv7 2003]

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.

[f1rocket]

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??

[GizmoGuy]

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

[f1rocket]

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.

[jonbakerok]

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!)