Hooking up a Headunit to a Computer PSU

[pwayzjellyroll 10+ year member]

Well I have an extra head unit layin around, and some speakers. I'm interested in building a cabinet just to stick them in for whatever listening. Not a HT setup or anything just something small (not so wide but tall) and enjoyable. Not putting in a subwoofer. So my question is (yes I did search) Do I want an AT or an ATX PSU and also do you guys know any links on how to do it? I did see something about req's website http://www.r3q.net but it doesn't seem to exist anymore. So any info or help would be greatly appreciated.

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[GSteg 10+ year member]

The AT PSU is a much older unit that you hardly find on computers nowadays. ATX is the more current and widely used. It's much easier to find an ATX than an AT at the store.

The style of the connecters are also different, but I doubt you'll be needing to power up a motherboard.

The main difference between the two unit is the voltage output itself. The AT is capable of producing: +5v, -5v, +12v, -12v. The ATX can put out the same, except now with +3v, and -3v. It doesn't matter what you're going to use because both will have that +12v output for you and connector style will not be as important since most people tend to cut out the connector and solder/crimp the wires.

You'll be using the +12v connection. I dont remember correctly, but I believe there are three wires (same connector that connects to your CD-ROM or hard drive). I'll need to dig up my old PSU to remember the exact connection, but it's really easy. I believe there are two black wires and 1 red. Red indicating power and black indicates ground (one or both?).

More on this later

 

[pwayzjellyroll 10+ year member]

I have access to both AT and ATX psu's at this time. I was thinking of using the AT due to the fact that they have the buttons that allow them to turn out. So I need to connect the red wire from one of the molex connectors to the red wire on the HU? Then just ground everything out? I just think it might be an interesting space saving thing to do, I figure I'll run 2 5 1/4's and 2 6x9's off of the HU.

 

[GSteg 10+ year member]

Yes use to 4-pin Molex connector.

+12v ignition (red) and +12v constant (yellow) will go to the power wire on the molex connectors. I would personally use a different grounding source for the headunit. The one on the power supply will often get you noise for many reasons. So basically, all you're using the power supply for is the +12v wire.

 

[pwayzjellyroll 10+ year member]

yeah I was figuring about mounting a metal plate or something and grounding through that? But you mean the red and yellow wires on the back of the HU will each have to go to their own red wire on the molex connectors?

 

[Ctminime 10+ year member]

//content.invisioncic.com/y282845/emoticons/needpics.gif.edd6d28e76618c28c46f343991bcced5.gif not everybody is gonna know what these things are maybe if u posted some pics for people.... its not that hard to do but not many people know for example what a Molex connector is....

 

[lilmaniac2 5,000+ posts]

molex connector

Google is your friend //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[pwayzjellyroll 10+ year member]

Don't have a digital camera ATM unfortuneatly. Once I get the concept down I'll do pictures of the build process and stuff I'll just have to borrow a camera from someone.

 

[pwayzjellyroll 10+ year member]

Google is your friend //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Thanks maniac. Yes google is your friend. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[GSteg 10+ year member]

yeah I was figuring about mounting a metal plate or something and grounding through that? But you mean the red and yellow wires on the back of the HU will each have to go to their own red wire on the molex connectors?

Yes. Something metal would be nice as long as it's isolated from the power supply.

For the red and yellow, you can run them together to one molex connector, or you can have red and yellow on separate connectors. I've ran both ways. I prefer using separate connectors for each one to satisfy my mental health

 

[pwayzjellyroll 10+ year member]

Heh, I would prob run them to seperate connectors just as one of those things as you stated. It would just seem more sensible to me if that makes any sense? Lol. I figure I'll mount the PSU up in the back right corner, a toggle switch in the front of the cabinet to allow power on or off. Hu in the middle with a fan behind it off another molex connector for cooling purposed. My other question was do I have to make seperate chambers for each speaker? Or would they be find in a common chamber.

 

[GSteg 10+ year member]

My new mission will be throwing a car battery into a house and using a charger to charge the battery overnight. No more dinky 12A from PSU //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[Rodge 10+ year member]

There are two pins you need to short on the 20 pin mainboard connector for the PSU to even turn on. I believe it's pins 14 and 15.

 

[pwayzjellyroll 10+ year member]

Heh cool I think read somewhere you need an SLA battery to do that? Btw not sure. Also do I need seperate chambers for the speakers? Or will they be fine in a common chamber.

 

[pwayzjellyroll 10+ year member]

There are two pins you need to short on the 20 pin mainboard connector for the PSU to even turn on. I believe it's pins 14 and 15.

On ATX psu's it's the green wire and a ground wire to turn it on. Not sure which pins but I do know it's the green wire and a ground. I figure if i put each of those ends on a switch it will either allow or cut the connection for power.