How to power a car amp with an ATX PSU

[bullzi]

It was requested of me to explain how to power a normal car amp with an ATX power supply to test, or to use in your home. So below i have taken pictures, and explained how to do so...

First off, here's a picture of my power supply specs, its just a cheapo psu i keep around for testing, yet its one i can always count on to work. First off you want to make damn sure your voltages are good, you dont want to fry your brand new amp... FYI: you don't need an amazing psu to be able to test the average amp, i used this psu to power an alpine 280 watt psu and it powered dual 5 1/4 speakers and a 10" sub just fine.

Next you want to locate your REM cable or remote on cable, this is almost always a green wire, that is always located on the 20/24 pin motherboard power connector. NOTE: there will only be one of these green wires. If you plan on using this power supply again for a computer or whatever, simply cut this green wire at about half length so you can easily attach it again after testing your amp. FYI: This green cable turns the power supply on and off, when the ground circuit is completed to this wire, it turns the power supply on.

This first picture is showing the green cable separated from all other cables.

After locating this green REM cable, you need to strip the end...

Follow this thread to the next post below...

 

[bullzi]

... Following from above...

Now that you have located and stripped the end off of the REM cable, find any black ground preferably cut off a molex connector because you will need the yellow (12V) wire later... Once you have cut off an extra molex connector strip the black ground wire and twist the green REM and black GROUND together... (Seen below on the left in the picture.)

Now, make sure no wires are touching except the BLACK and GREEN. Plug-in the PSU and instantly the PSU should start up and you can notice the fans running.

If the PSU doesn't turn on, then either there is a wire touching somewhere causing a short, or the GREEN isnt the REM wire... and at that point, i'm not sure what else is the REM wire...

If the PSU did turn on, and its working good, then your and can move on.

Now that you have the PSU ready to turn on, all you have to do is strip the YELLOW wire that is left over from the molex connector that you cut off. This YELLOW 12V wire is the main power that will be feeding your amp.
(It is the middle wire in the picture below, refer back to this final picture from the bottom.)

Alright time for the last stretch! Finally you are ready to prepair the amp's REM wire. The AMP's REM wire does the exact same thing as the REM wire does for the PSU, when current flows to this input the AMP will power on but will not draw power from the REM wire, it will draw the main power from the lower gauge 12V input. I've learned that you can splice the same wire you are using for the 12V power and use it for AMP REM, not sure why, but it just didn't work for me. So, what i did was cut off one of the floppy connectors and use the YELLOW wire from it for REM. All you have to do is strip the yellow wire and there you have your AMP REM.

FINALLY!!! Alright, you've made it this far, just a bit further!

Below is a table of inputs and where they all go to power the amp.

AMP GROUND = BLACK and GREEN REM FROM PSU (both still twisted together)
AMP 12V = Thick YELLOW 12V from MOLEX
AMP REM = Thin YELLOW 12V from FLOPPY

This is not full proof, these are "suggestions" of how to do this. Therefore I am not responsible for any damage done.

Now all you have to do is plug in your PSU and your ready to rock!

Kyle

 

[Juice1]

That's confusing... lol is there a way to use a PSU as an amp?

 

[bullzi]

psu as an amp? not that im aware of, but there's a way to power an amp with PSU as said above

 

[Rubber314Chicken]

I saw tutorial once where the guy took all the wires out and just put the single prong banana jacks on (i don't know what to call them), labeled it, and had a switch for it. it looked really nice (very clean), but if you ever want to use the psu again for comp stuff this is the best way.

 

[Ð88]

Nice, if i had a spare PSU laying around then i could test your instructions

 

[bullzi]

indeed you could, i would put up the pic. of it powering my alpine, but its already in my jeep... i have one week till my birthday, its crunch time to get the jeep done!

 

[Half Evil]

I cant wait to try it, now I just need a PSU.

So, I have a 1300wrms amp... How many watt psu should I get for something that. Because its not average..

 

[setishock]

For testing I suggest putting a switch on the green and one of the black leads. Toggle or rocker would do fine. Just dress up the connections with shrink boot. Just skin back the insulation somewhere along the line between the psu and the motherboard plug and attach the switch That way you can kill the psu right quick if need be and it looks better.

 

[Lowndsey]

Bullzi I would be putting some sort of disclaimer on the tut because if someone follows that wrongly and burns their house down i wouldn't want to be in your shoes.