Creating Auxiliary Audio Input on Stock '95 Radio

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Okay, really simple. I went through a lot of car stereo discussion on another thread a couple weeks ago. Bottom line, the radio plays clearly and loudly enough, but the MP3 player through a FM broadcasting device to play through the radio does not play as loudly. (I have the MP3 volume at 24 out of 31, any higher produced distortion, but the MP3 played fine in my buddys system with subwoofer and high power, so the MP3 is not the problem, but seems to be the radio broadcast transducer). QUESTION 1: Can I get a higher volume level by hooking it direct to the radio instead of through the FM broadcast device? IF YES, THEN QUESTION 2: The radio is the basic one in a '95 F150. I have two, one with a cassette deck. I am thinking there is no audio input on the back, nor would any of the wires in the harness be audio input. But what if I can get at the wiring for the cassette deck, basically hook an earbud cord to the two wired receiving cassette input, then plug the MP3 player in direct. Would it work? This would also be nice because then I could eliminate the radio broadcast devise and hassling with it every time I fire up the truck. Thanks
 
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I have a DEI FM modulator with some Ford antenna adapters that I no longer need (replaced the head unit) that I would sell you at a decent price if you were interested. Alternatively, replacing the entire headunit would be a worthwhile upgrade. For about $130 I installed a Kenwood 50Wx4 headunit that has a USB port to play MP3/WMA files straight from a USB flash drive (as well as play from and control an iPod) and it also has a front aux input jack.
 

TallPaul

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Yes, it broadcasts over the air and I can pick it up in a separate vehicle up to 100+ feet away--interesting effects for passing cars, eh? Chevrofreak. I'll pm you, that sounds like it might be just the device I need.
 

TallPaul

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Alternately, I can wire the MP3 inut direct to the radio amplifier. Would need a switch to go from radio to MP3 (or just ditch the radio). Possibly install a jack in the radio face plate (the one w/o cassete has big empty panel on front. I suppose splicing into an antennae plug would not work as it is not a radio signal coming out of the MP3, hence the need for a device like Chevrofreak has.
 
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TallPaul, thanks for posting this topic and thank you to chevro for the FM modulator idea. I'm thinking about buying this one as it good reviews: http://www.amazon.com/Scosche-Audio-FM-Modulator-Universal/dp/B0007THIDQ Two selectable frequencies so there's no need to have an external radio signal. Are there different quality FM modulators when it comes to sound quality? The XM-provided one we have is only OK when it comes to music quality. The Griffin cigar-lighter plug in FM tranmitter for an iPod has far superior clarity then XM FM Mod thingy.
 

TallPaul

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Nice link ToyotaNSaturn. At the bottom is a link to a earphone to RCA splitter. I wonder about sound quality, which is why I would like to wire in directly. BTW, my other MP3 player works better through the FM transmitter. Both play same volume level and sound great on headphones. I think the equalizer selection is not good on the one and may be a large part of the problem, but I also think there is some distortion that does not show up on headphones. Seems to perform better backing off the MP3 volume and overdriving the car radio amp somewhat.
 
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Any kind of FM modulated input will not be as clear as a direct input. While those antenna-mounted ones are usually better than the FM-transmitter type, Both are hindered by stereo separation, and FM's maximum 15Khz bandwidth.
 
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On older radios you could inject an audio signal across the volume control potentiometer. I expect the radio in the F150 doesn't have a volume control potentiometer (probably has a chip with that function instead), though, so it won't be that easy. You could go straight into the audio amplifier chip. This wouldn't be volume-controlled except by your mp3 player.
 

JHZR2

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I have one that goes inline with the antenna. While it works well, it still needs me to turn up the volume on the player and the head unit to get adequate volume. The best one that I have is a Becker-performed mod to a Becker Europa (IIRC) casette deck from a 1983 MB. It has a standard female plug, and when the circuit is completed by me putting a player into this input, it cuts out the cassette and radio input and plays loud. No need to turn anything up. Somehow completion of the circuit cuts out all but the aux input. I dont know how, but perhaps some way like Brian mentioned above. Iterations of this deck were used dating back to the 1960s in various high-end euro vehicles.
 
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You can get 1/8" jacks that contain a switch which breaks the circuit when a plug is inserted--like Radio Shack #274-249. All you have to do to make these work is find the Left/Right input from the tuner chip to the volume control chip, route it into the 1/8" jack, and then from there to the volume control chip. Then when you insert the plug from your MP3 player it cuts the output from the tuner and inserts your MP3 audio in it's place. (This might be a problem if the same chip controls both the tuner and the volume--in that case you could insert the jack between the volume control chip and the audio amplifier chip, which is almost guaranteed to be a separate chip).
 
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There are factory radios for sale on Ebay in which people have added the input to the front. Finding where to solder the wire in is the tricky part!
 
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There is another possibility--is the radio in your F150 the single DIN one that has an outboard amplifier? If so, these have a socket on the back that is used to connect a separate CD player. Normally there is a jumper plug installed there which connects the left/right output of the tuner/tape circuitry to the input of the volume control. Removing the jumper plug and making the appropriate connections will allow you to feed line-level mp3 audio into the unit.
 

TallPaul

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So best to hook in before the volume control. What about bass and treble, are they also in the volume control chip? I don't know what a single DIN is, but there is no external amp, seems the amp is on the side, but within the case of course. I looked and did not see any connection on the back, but maybe there are some spare pins in the female slot on the back. I'll check as that would be a lot easier.
 
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Single din is roughly 2" tall. If the radio is taller than it's a double din or din and a half. I forget what Ford used in the '95 F150. Typically bass and treble are also controlled in the chip that does the volume.
 

TallPaul

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Yeah, it's roughly 2" tall. Does that one have aux imput tabs in the socket where the two wire plugs connect? Whatever DIN means?
 

JHZR2

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 Originally Posted By: brianl703
You can get 1/8" jacks that contain a switch which breaks the circuit when a plug is inserted--like Radio Shack #274-249. All you have to do to make these work is find the Left/Right input from the tuner chip to the volume control chip, route it into the 1/8" jack, and then from there to the volume control chip. Then when you insert the plug from your MP3 player it cuts the output from the tuner and inserts your MP3 audio in it's place. (This might be a problem if the same chip controls both the tuner and the volume--in that case you could insert the jack between the volume control chip and the audio amplifier chip, which is almost guaranteed to be a separate chip).
Interesting... I wonder if my c. 1970s technology radio has all that inside? I kind of figured t was a bit more old-fashioned...
 
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 Originally Posted By: TallPaul
Yeah, it's roughly 2" tall. Does that one have aux imput tabs in the socket where the two wire plugs connect? Whatever DIN means?
No, only the ones that have an outboard amp have the aux input jumper on the back. You can tell that it has an outboard amp because it will have an 8 conductor cable (usually gray) connected to it with a 4x2 plug, which goes to the amp. If it just has a 1x8 plug with individual wires connected to it, no amp. DIN is the standard size specification for the radio.
 
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 Originally Posted By: JHZR2
Interesting... I wonder if my c. 1970s technology radio has all that inside? I kind of figured t was a bit more old-fashioned...
Probably not. The later-model Ford radios didn't have any knobs on them, the volume is digitally controlled in step by up/down buttons. If I'm mistaken about the radio used in the '95 F150 and it is the older style with an actual volume knob, then you may be able to hook the aux input to that.
 
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 Quote:
Whatever DIN means
DIN stands for 'Deutsches Institut für Normung' which is the German national standards institute. When referring to radios, when someone says "DIN-sized", its measurements are approximately 2"H by 7"L. A "Double-DIN" reciever (those big stereos that seem to come with almost all newer cars nowadays) measures approximately 4" H and 7"L. DIN is pretty much the standard for car audio sizing today.
 
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