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Alternatives to my car's radio

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ikalogic

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Hello,

My car's radio is dead. i've identified all the wires going to the speaker, 12V power (and also the wires for volume control near the driving wheel)

What i want to do do is simply to connect my MP3 Player, or any audio output to the speakers. Sure, i'll need an amplifier for that, and that's why i am asking for your help: I know nothing about audio!

I am searching for the simplest solution..

The speakers are 4 OHM speakers (there are only 2 speakers)

I have a lot of TIP transistors.. hope i could use those ones if i have to build a circuit.

I am also thinking about something else, but maybe i am wrong: If i buy a cheap set of speakers, that would usualy be pluged to 220V, open them, take away the (most probably 220/12) transformer, and use it directly on the cars power supply..sure, i will connect it to the speaker of the car. would that work?

thanks for your help.
 
I've found this circuit:

**broken link removed**

It seems simple enough for me to be understanding what i do. but not enough powerfull, what would i need to do to boost it power a little?

Also it use TIPs, so good, but can i use TIP122 instead? (i don't have TIP31).. what changes would i need to do?
 
You found a very distorted very old amplifier circuit that might produce 1W into a 4 ohm speaker.

A cheap amplified speaker with a 12V adapter probably has an output power of only 1.3W into an 8 ohm speaker. A 4 ohm speaker will blow it up.

A car's electrical system is usually 13.8V. A bridged car radio amplifier IC has an output power at clipping of 14W into a 4 ohm speaker. The bridged amplifier is two high current amplifiers with each one driving each end of the speaker for nearly double the voltage across the speaker. Then the power is 4 times as much as a single amplifier circuit. The speaker is 4 ohms then the current is double the current of an 8 ohm speaker for additional power.

The TDA7240A amp IC is easy and the pcb design is in its datasheet.
 

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A cheap amplified speaker with a 12V adapter probably has an output power of only 1.3W into an 8 ohm speaker. A 4 ohm speaker will blow it up.


Blow it up speaker or amplifier ?
 
Nearly anything will blow up a cheap speaker.

An amplifier that is designed for an 8 ohm speaker will try to drive double the current into a 4 ohm speaker. The over-current will blow up the amplifier.
 
Just find a cheap car amp (flea market, pawn shop, scrap yard, yard sale, crack dealer, unlocked car). Low watt amps are almost free, most people upgrade and have no use for the weak ass junk. Worst case, you might need a small pre-amp.
 
I just picked up a Panasonic tuner/CD/MP3 deck at a yard sale for $5. I hope to install it in my wife's Subaru before the transmission falls out of the car.

Another idea (which is still a project) is to fix the car radio, and as a bonus, add a jack where you can plug in the MP3 player. Maybe a buffer would be needed too.

In what way is the radio dead? Just doesn't power up? Or something else?


Torben
 
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