car stereo in computer?


Aug 29, 2005
are there any problems with putting a car stereo in a computer? Car stereos run on 12v power, right? Thanks.

Theoretically quite possible and easy. But it will pull a few amps off the 12v rail and produce some heat. If you're just looking for an easy integrated amplifier that runs off 12v, there are better choices.
The magnets from any decent sized car stereo would wreak HAVOC on your system if too close. I have seen car subs hooked up before though.
Fenris_Ulf said:
Theoretically quite possible and easy. But it will pull a few amps off the 12v rail and produce some heat. If you're just looking for an easy integrated amplifier that runs off 12v, there are better choices.

What other amplifiers are they?

I have this huge reciever that I want to replace with a minimal amplifier because I only need it for my computer. I would like to only connect my speakers directly to my computer but I havent found any internal amplifers. 25 watt is enough.
The Sonic Impact amp is 15W x 2 channels. If you dis-assemble it, the PCB is only about 1" x 3" and can easily be tucked in somewhere in the computer. It runs off of 12v DC (you will probably need a smoothing capacitor or two because the switching power supply in a computer produces lots of noise on the rails), is very efficient, and gets rave reviews as approaching an audiophile amp. I would recommend efficient speakers with it since like all amps distortion increases with gain, but it should be fine will all but the most inefficient speakers.

Heres a link to one for sale .

This idea has been on my mind for a while I have an older Alpine stereo and an old Craig 10 band graphic equalizer. The equalizer would fit into a bay without any problems but the stereo is a bigger than a standard cd rom so you probably need a horizontal case I use rack mounted cases so that wouldn't be a problem.

So let look at some of the obstacles we would have to deal with that have already been mentioned.

Amperage: how many amps will it pull off the power supply?

Heat: car stereos get hot so how much heat will you be introducing into the case?

Is there a magnetic field and how strong is it?

And some sort of filter to clean the power coming out the power supply.

For the EQ I was wondering if it was possible to hook it up to the sound card for hardware EQ instead of using the software based stuff that usually comes with sound cards.

I'm sure we can find a way to make this work properly. I don't know if this will ever become a fad but at least we can say we did it.
The biggest issue would be that you have a stereo that expects constant 12v power hooked to a switching PSU. For one, you'd need to build your own power filter that had some fairly nice sized capacitors on it as well as some IC's to help the variation in power. Secondly, most car stereo amplifiers introduce a large magnetic field that would really screw with your other components in the case. (Faraday cage maybe?). Thirdly, how would having that amplifier connected to the same PSU as the other computer components affect each other? You could find that hard drives, and CPU's and RAM all start to not work at some point due to the EMF send backwards from the amplifier... and what happends of the amplifier clips? where does that power go?

I have a feeling this just isn't a good idea...

Now... what would be cool is to have a large case with 2 PSU's and have the amplifier built in that way.

Search Google for the ultimate gaming machine made by Yoshi (Tech TV guy).

It had like 4 console machines, a PC AND built in amplifier.
Get a 110vac to 12vdc voltage converter at Radio Shack or any auto parts store or truck stop, and simply run a cable into the back of the box. (I've had this idea for a long time myself.) But for me the hard part is trying to config the PC audio outs to the car stereo ins.
Get a mini-ITX PSU, use an AC power splitter cable, adn run it that way. Also consider modding the back of your PC to fit banana plugs for your speaker outputs. The ideal stereo for this would have RCA inputs on the back, so you can loop your soundcard's output (stereo only) into it and use it as a universal volume control.

I done this years ago with a Panasonic CD just was not installed into a computer, just a desktop ran unit running off a spare AT power supply.

As for speakers, you can use regular 8-ohm home speakers if you's OK to use higher impedance speakers than your amp's ratings....just avoid going lower.
Good points every one, I use 4U server chassis for my cases and I have them in a 42u rack so I could use a case that has a couple of power supplies in it. But is standard power supplies aren't going to work then I can stuff an ac/dc power converter in it. in there too.

Ok so I think we have the power figured out. I get the feeling it would be best to isolate it from the power supply that the system is using. Do we have any car stereo Geeks in this forum that can tell us if or how radiation or electrical noise that older car stereos would cause?

And do newer car stereos cause less radion or noise?

Ok so this particular radio has rca jacks for front and rear out. and a cd changer in port. How would we configure the sound out to the sound card so you would get sound properly.

What brand and model of sound card would we need?

Would we need any kind of adapter to go between the stereo out and the sound card in?

I also just had the thought that maybe instead of cramming this into my gaming system I will take a 2 or 3u server case and turn this into a stereo MP3 server I can mount into my rack.
You don't want that going into your seound card, you will over-amplify the signal. The RCA outs on that stereo are not line out, they are preamp-out. You can try feeding it this way, but you will get annoyed very quickly.

Preamp outs are variable output vs the static output level of a line level signal.

If you want ot do this, you should use the stereo as the device your soundcard feed it's signal into you need RCA INPUTS for that....some radios have them, some don't.

Either way you do it, you MUST use a quality shielded cable (source anchored Quad-shielded preferred), as the inside of a computer is chock full of electrical noise that will find it's way inside of those preamp or line level cables.

As for if the soundcard is a line level or preamp level, look at the max signal voltage....the soundcard will rarely be as high as a car stereo's preamp signal the case of 2V preamp outs, those can damage the input stage on some soundcards.
Yes you can power a car amplifier from an ATX PSU, but there are several issues that would arrise of mounting said amplifier actually inside a running computer case.

1.) The power concern - a car amplifier pulls a very large current from the 12v rail, which means that you would either need to have an imensley powerful PSU, or use a separate PSU for the amplifier.

2.) Also on the power note, a computer PSU isn't designed to supply spikes in current that an amplifier draws when a heavy bass beat plays, & as such, a car amplifier could damage the PSU (this is why I have only ever played around with car amplifiers using old spare PSUs that I was planning on throwing out anyway).

3.) The EM field generated by the components of the amplifier would at very least cause much unwanted interference, & at worst could ruin your hardware.
Ok car amps are all around bad for the pc. So what about the 10 band graphic equalizer could that be used as a hardware based EQ for a sound card?
Ok so amplifers in the or around the PC is bad, be it a stereo with an amp built into it or a car amp either is just going to cause trouble for you. Plus giving the stereo the right power that isn't connected to your PC's psu is another problem.

So what about a 10 band graphic equalizer that was originally in a carmade to work with a car stereo. How about using it as a hardware based EQ for you sound card. Or more aproprietly sound coming out of your sound card.

So here is what I have a Craig brand 10 band graphic equalizer amplifier. So for the sake of this discusion lets just say we are putting the EQ in a seperate case from the PC and we are powering it with a proper power supply that isn't the PC's power supply. And everything is propperly shielded

Here's how the wires are marked on the back of the EQ:

DC 12v in
Source ground
Power ground

Right signal input positive, Right signal input negative
Left signal input positive, Left signal input negative

Front right positive, Front right negative
Front left positive, Front left negative

Rear right positive, Rear right negative
Rear left positive, Rear left negative

So is there any way to feed the signal from the sound card to the EQ and then back out to headphones, stereo, etc.

What kind of connectors would we need to go from one item to the next?
Is this a preamp-only EQ, or is this an "EQ-amp" that has speaker level outputs?

That was what people were getting at, is the potential for problems when running an smplifier inside the computer's chassis.

Running it next to the computer will be no problem, so long as there is not electrical contact with the computer chassis. A computer case is in essence a Faraday cage, so it will shield the components inside quite well (also why servers don't have windows in them, they allow EMI).

Really, this isn't a bad thing to do, but it has to be well thought out for it to work right. Lots of variables when introducing an AC signal inside a computer case (audio is AC, the variable AC frequency makes it far worse than a mains line inside the case {as in watercooling})

However, that can be resolved through proper shielding and grounding techniques.
You guys have been really helpful thanks. I use server chassis for my pc because in my mind PCs are tools that you use but shouldn't have to see or work around, or take up space on your desk.

These cases are very solid steel cases for the most part and are probably more resistant to allowing EMI out than the standard PC tower with the display window on the side. I use standard motherboards and components just like every one else I have not used any server components at all.

As for the EQ it is a Craig brand 10 band graphic equalizer amplifier where you hook it up to you stereo and then to your speakers. The diagram doesn't say anything about running an amplifier in the circuit. So it is its own amp to.

So I understand that we don't want to run an amplified signal to the sound card because we might blow it up. So lets focus this discussion on the input signal coming from the sound card to the stereo equipment and then out.
OK, first to dispel a few misconceptions:

A car stereo, properly designed, shouldn't leak any magnetic interference. If there is any RFI emissions, it would probably come from the switching PSU in the amplifier, but most car stereo "head units" wouldn't even have a switching PSU. You can tell because they are marked as having something like "40 watts per channel", which really means that they are 8 watts continuous (into 8 ohms) and 40 watts for a millisecond. They use a differential output single chip amplifier which runs off of the 12v car supply. They shouldn't leak any effective RF. A car power amp will have a switching power supply in it since that is the only way to effectively get the voltages necessary for high power. Depending on the design, there could be RF leaked to the outside, but I don't think that's what we're talking about here.

What this really means:
Power: A car stereo head unit would be just fine in most computers as long as there is sufficient headroom on the 12v line of the PSU. If you're not sure, use an old AT or ATX supply or a sufficiently beefy linear power supply. Since old AT or ATX PSUs are dirt cheap, that's probably your most cost effective route. Next, find a surplus "computer grade" capacitor of sufficiently large value (25,000 uF should be sufficient) and put it across the 12v line for smoothing/power reserve.
Input: If the head unit has an input (many newer ones have a 3.5mm line in jack), just connect the soundcard output to this. If the head unit has RCA in jacks, use those with the appropriate 3.5mm to RCA adapter cable. If you don't have a line in, then you're screwed. Any workaround will be more of a PITA than it's worth.
If you want to get the stereo to go into your sound card to play through your computer speakers, you have to have RCA outs on your head unit. Just use a 3.5mm to RCA adaper cable to connect to the "line in" of your sound card. But you could just buy a Griffin USB FM tuner and be done with it. If you don't have a "line out" on the head unit, it's a crapshoot. Most modern head units don't have one speaker line tied to ground like a home stereo. This means that using a "line level converter" which takes the speaker outs and converts to line level, probably won't work. The grounds would have to be tied together and since there is no ground, the results would be unpredictable. Car stereo amplifiers get around this by providing virtual grounds and buffering on the inputs, but if you wanted to go to this much trouble, you would be better off with other solutions.

If you're looking to use car stereo components for amplification out of your computer, then that's possible. If the equalizer has "line in" or low level inputs, just use those. If it has only high level (amplifier) inputs, then it needs a large signal to work, and a soundcard just can't produce that.
Ok... maybe I'm missing something here, but why do you even need an amp at all?
You could easily just go from your soundcard to a pair of monitor speakers that have the amp built into them. e.g.

I mean if you really want to attempt to put a small amp into a PC then by all means have at it!
I just think this would be a simpler more elegant solution.
Ok nice work Fenris_Ulf thank you. So here is the point of all this is I have car stereo that in its time was a high end stereo and is still a good stereo. The only thing about it is that it is older and wouldn't what difference between an MP3 and a pancake was. Because it was built before everything started to play MP3's, it doesn't have USB either.

SO instead of giving it away or leaving it on a shelf until hell freezes I thought I would slap it into a computer and use it for music or as some had said as an amplifier for the for the PC.

Again and I have said this several times now I would run sound from the PC to the in on the stereo NOT the other way around.

My point was to use the stereo in a new creative way that could give it new life and not fall pray to this "its old so lets throw it away and get the latest and greatest one" mentality.

Here are the guide lines for this project

1) I want to install a car stereo system into a computer case. Thats the stereo, amplifier, equalizer, maybe even an in dash dvd screen if I can find one cheap.

2) I want to be able to play am, fm stations, Cds, on it and use the line in for my other computers to use it as an amp.

3) Decide how to hook it all up so it works, What type of power supply, what type of filters to use. What kind of ports to put on the back of the computer so I can run speakers off of it.

4) Put it all together and test it, take pictures and write up a parts list and a schematic so other people can duplicate the process.
2) "and use the line in for my other computers to use it as an amp."

From what you said previously you'll probably have to mod the "CD Changer In port" to a line in port. Something like:

If you ran the stereo off of an independent power supply this would allow you to use it while the computer was turned off as well.
3) "What kind of ports to put on the back of the computer so I can run speakers off of it."

You could take a 3.5mm Stereo Phone Jack like these:
and wire up 2 of them in a PCI slot cover (for example) as front right/left and rear right/left.

Hopefully this'll give you some ideas.

For speaker level connections, you can also use binding posts, which will let you use bare wire and such for your connections. Just be sure to use a plastic plate around the posts, to avoide the wires shorting on the case.

Here's a link to a picture of some examples of binding posts...the black/red single unit pair can be bought in ratshack.
Ok good idea does any one have an appropriate power supply in mind? It needs to power your average car stereo, Amp, EQ, Maybe a disc changer.
What kind of amplifier are you talking about? A car amplifier bigger than 50w x2rms is well into "dream on" territory, a 280w PSU won't even get it breathing.

A car stereo, look at it's power input specs. 12v x amparage on fuse (let's say 5a) will give you your wattage (in this example 60w). So that would be your spec for your radio. Do this on EVERY component, and then addit up. Get a PSU with at least an extra 25% continuous power output to assure clean stable power, and there you go.

Reason that 50x2 amp won't run off of 280w RMS is this: the amp rating is output wattage, and the input wattage is far higher. Assuming 50% effiiency (damn good for most car amps), you are going to pull 200w on the input power....can your 12v rail deliver this? In most cases, hell no!

If you want to run a car amplifier get an industrial 12v ready to pay money, and be ready to make some kind of protective (electrical and EMI) cage around it. I reccomend Power One, as I have professional experience with them, they make solid stuff.
The magnets from any decent sized car stereo would wreak HAVOC on your system if too close. I have seen car subs hooked up before though.

where do you think the most powerful magnets in your home already are, there inside your hard drive. other then a floppy there aren't really any magnetic sensitive parts in a computer, besides, look at your case fans, guess what, theres magnets in there!
where do you think the most powerful magnets in your home already are, there inside your hard drive. other then a floppy there aren't really any magnetic sensitive parts in a computer, besides, look at your case fans, guess what, theres magnets in there!

True, but if he is using a CRT, they can screw that up pretty badly.

I ran unshielded speakers next to my computer when it had a TFT for years, and no's just when using CRTs that problems arise.
We will found out if the shielding is a problem after we build it. So I am thinking of putting this in a 3U rackmont case. Will any of those industrial powersupplies fit in that form factor?
Yes, but not in the way you are assuming. They don't fit into the PSU bay. You will have to just make a Faraday cage in the 5.25" bay area and mount it in there. make sure you have proper airflow through that cage as well.

Here is a link to a picture of one:

That core is VERY similar to the one I've worked with for years.
So the Faraday cage needs to be around that power supply so it won't send errant radiation the other electronics in the case? And what is the model number of the powersupply you are suggesting?
Yep, you need some kind of shielding for that...those things produce a good amount of electrical noise. And don't forget some kind of cooling....those things run hot.

I didn't pick out a specific model here...but all you have to do is pull up an electronics supply catalog and look for what they have to offer. Condor/Power One is one of my favorite brands,just from being so familiar with them.

That pic was more or less just to show what kind of form-factor those things have. Some are single-rail, some are dual-rail. A Single-rail will do a car stereo just fine (car stereos run on +12v constant for clock and primary power, and +12V switched to turn it on.
Sorry for digging up an old thread but I successfully jumped my ATX power supply with a piece of wire and hooked my car stereo up to it. :)

The only wires on the head unit you need to use are the 12V constant, accessory wire, and ground.

Sorry for digging up an old thread but I successfully jumped my ATX power supply with a piece of wire and hooked my car stereo up to it. :)

The only wires on the head unit you need to use are the 12V constant, accessory wire, and ground.

Yep, looks good!

The accessory wire is the +12V switched I was talking about.

To get a working radio antenna, you will have to modify the hell out of an RCA plug, or get your hands on a car antenna cable.
another old thread dig but you don't really need to do any modding to get a working radio antenna, a piece of bare coper wire (solid) can be used as an antenna. the copper wire I have is probably about 12 gauge and I found it at a gardening store.
I run my Sonic impact off of my 12v line, with no filtering capacitor. When I was using a 7300gt there was virtually no noise. Now that I have an 8800gts, my Seasonic 430 gets pushed a bit more so there is some noise, however Im inclined to believe its from the onboard sound more than the impact.

Just my 2c. Also, I have very sensitive drivers, so with duller speakers, like computer speakers, you might not notice the noise at all.