Convert car stereo to home stereo

[BigEdgar]

Hi,

I want to turn a car stereo into a radio for our house. What I really want is a good AM radio receiver, and it turns out that most car stereos have much better AM receivers than any other radio out there (trust me, I've tried everything from expensive "super radios" to running a wire antenna way up a tree). And I don't want to invest in satellite radio. I can't get any good AM reception in any of our in-house radios, but I get great reception in my car when it's parked right out in front of our house.

I happen to have an old car stereo and have thought that I could hook it up to a 12V transformer, an antenna and some speakers and see if this setup works as an AM radio for the house. What I need help with is wiring the radio for AC power. I have an old 12V wall wart transformer, and I think all I need to do is properly sodder the wires from the radio's wiring harness to the correct wires on the AC transformer, right?

(And yes, I understand that I risk shocking myself, popping a breaker or bricking the radio with this project - I've done other similar projects and had all those things happen before : )

Assuming my plan will work, which wires should I hook up in what manner? The wiring harness on the radio will have three wires that I think I care about:

• red switched 12 volts
• yellow constant 12 volts (usually hooks up the vehicle battery to maintain stereo memory)
• black ground

(Other wires include blue/white amp turn on, blue power antenna, orange dimmer and a bunch of speaker wires, none of which matter for the power.)

Anyone have any thoughts on how those three wires should be soddered to the wall wart wires?

Anyone else have any other gotchas that I should be thinking about?

Thanks for any assistance.

 

[squishy36]

First find out what current the radio will draw -- this will then help you decide if the wall wart has sufficient current output. There are two other things to think about: make sure the wall wart puts out a DC voltage; some of them are AC warts. Most importantly, you'll probably find that the wall wart isn't regulated or regulated very well. This means it probably won't work very well for your radio. You may want to purchase a power supply intended for such use; for examples, type "12 volt power supply" into e.g. Amazon's search. As to wiring, it sounds like you'd just hook up the red and yellow lines to the +12 volt output of the power supply and the black to the - output. Realize that if you want to maintain the memory, you'll have to leave the power supply on all the time.

 

[Reloadron]

The only consideration is the current draw of the radio you use. A basic stock AM/FM car radio won't draw much current but if you get into a high end system and amplifier you will need one hell of a 12 volt power supply. Beyond that it should work fine.

Squishy beat me. Started the post, went to turn the roast and beaten.

Also, I would use a basic 12 volt power supply of maybe a few amps minimum. There is no need for regulation as an automotive system is between 12 and 14.5 volts give or take.

Ron

 

[BigEdgar]

Thank you both for the great feedback. The radio doesn't indicate the current draw, but the car has a 7.5 amp fuse for the radio, so I assume that it draws 7.5 amps max (likely much less). I'll look at what power supplies I have and head on over to Mouser if it doesn't look like I have something that will meet my requirements.

 

[audioguru]

Are you deaf to high audio frequencies?
AM radio (Used by old grandmothers) cuts audio frequencies above 3kHz. Only vowels are played and the important high frequency consonant sounds of speech and the important harmonics and percussion of music (up to 20kHz) are not played. AM radios play all kinds of interference.
FM radio sounds much much better.

 

[Reloadron]

Are you deaf to high audio frequencies?
AM radio (Used by old grandmothers) cuts audio frequencies above 3kHz. Only vowels are played and the important high frequency consonant sounds of speech and the important harmonics and percussion of music (up to 20kHz) are not played. AM radios play all kinds of interference.
FM radio sounds much much better.

Maybe he likes "Talk Radio" or "All News Radio"? I leave work and on the way home have a talk radio show that I like. Yep 1100 AM works for me. Well unless there is a thunder lightening storm. Therefore, respectfully screw you for inferring I am an old grandmother! So there!

Ron

 

[Zerotolerance]

Simple... Use a psu from a computer

 

[JimB]

Simple... Use a psu from a computer

Or maybe not.
Computer PSUs are switch mode devices and usually generate a lot of RF noise which will wipe out the reception at long and medium wave frequencies.

Better to get a simple linear power supply.

JimB

 

[BigEdgar]

AM radio is used by grandmothers .... and sports fans. While FM sounds better for music, I've never missed a play on AM radio where I had good reception. Works for me (and apparently it works well enough for most broadcasters in my state, as it's tough to find any sports on FM).

 

[JimB]

Dont worry about golden ears AG, I think he listens to bats. Maybe talks back to them sometimes!

There are those of us who cant hear much above 5khz anyway and have tinnitus screaming in the head half the time (like just now) who just appreciate radio in all its forms.

JimB

 

[Reloadron]

@ BigEdgar and JimB

Hey, yeah, I forgot about the sports. Thanks.

Following a number of years around jet engines and maybe a few too many trips to the rifle range my hearing isn't what it once was. Hell, AM sounds fine to me. Many years ago during my ham radio days it was enjoyable to listen to AM (Broadcast Band) on a good selective receiver with a dipole antenna during the late evening hours. You would get all sorts of channels. Sitting on LI, NY it was a big deal to get WGN in Chicago back then.

I am far from an audiophile but the wife thinks nothing of having a 2K sound system in her truck. No, she is not a bass freak who drives around pissing people off. She just appreciates her music and has great hearing unlike me. Years ago I had an old truck with a single speaker hanging from a wire under the dash. Sounded OK to me.

Ron

 

[audioguru]

People who played with guns have a high frequency hearing loss. I am an old geezer and I heard "ultrasonic" burglar detectors when I was young and now I can still hear the 15750Hz from a CRT TV because I never played with guns.

I was in my son's car and he had the AM news turned on. The treble tone control was turned up to maximum and speech sounded pretty good. But the music during commercials sounded awful.
My local TV station turns down treble frequencies during their newscast so that the announcers are talking in only non-undestandable vowels. I think they call it de-essing but their commercials sound normal with a flat response up to 15kHz. Their chief engineer must be deaf to frequencies above 500Hz.

 

[KeepItSimpleStupid]

Well CD's sound like crap to me which means listening to FM sounds now like crap too. Very high end FM receiver. It listed for $460 in the 80's for FM only. Then there is an FM signal processor which was about $225 and a dynamic range expander which was $500, list $1000. Preamp is flat to 100 Khz and the amps -3db frequency has been intentionally rolled off at 40 Khz, otherwise it extends to 800 Khz or 0.8 MHz.

I'm one of those guys that say valve amps sound better. Heck, I had one of them (Blaupunkt) in my car in the 80's with a solid state vibrator of my own design.

My amp was up against a Mcintosh tube, Klipsch voice of the theater speakers (horns) and the test was favorable. The Mcintosh lacked bass but drove the horns better probably because of the higher available voltage.

13.8 V power supplies are common: https://www.amazon.com/Pyramid-PS12KX-10-amp-13-8-volt-Supply/dp/B0002JTD1Q

A wall wart may be problematic. A 1 amp, 12 VDC wall wart would only supply 12 Watts,

Way back when, I worked on a tape deck (might have been 8 track) radio and a 10 A supply was inadequate. It needed a larger current to change tracks.

 

[audioguru]

I bought a Blaupunkt AM-FM cassette radio for my 1975 German car. I ordered its service manual but the radio was not German because the Chinese manufacturer's name was blanked out with a felt-tipped pen. Its cassette deck recorded in stereo and I souped it up so it was hi-fi.

 

[4pyros]

You will need a good filtered power supply and a good antenna. You may have to much interference in your house.