Need car sub help please.

Hey guys!

Id like to apologize if i posted this in the wrong section seemed appropriate.

Im just about pulling my hair out trying to find out what works here.

I have a 400W Computer PSU that im currently using to power my subs.

Now ive been using this PSU for a while now and really hadnt thought about this. I wonder though if im under powering my amp.

I have connected one yellow wire (12v) and one black wire (gnd) to the appropriate places. Now i have about 7 or so separate yellow wires and about 9 separate black ones and i was wondering if i needed to hook up "all" of them to the amp or just one of them. From what i understand all of the yellow wires are 12v and all of the black ones are the ground.


So would i be getting 400W out of just one wire?

For the info my subs "work" but i would like to get the most of what i can out of them.

Thanks for the info

No.

I properly converted ATX PSU with have all the same colored wires (voltages) connected to each other. A typical 400W sub AMP will draw something up to 40-50A on a bad day. A 400W PSU will be able to provide 400W when all V rails are maxxed out for current. 180W to 250W is more typical on the 12V rail alone.

To properly power a sub amp in the home, you will need at least two (3 is recommended) ATX power supplies connected in parallel to each other's 12V rails. It would be fine if you left the case grounding in place.

Find two psus with >19A available on the 12V rails, and you should be fine. Make sure you are using all of the 12V wires available, and make sure the ground wire between your amp and PSU is AT LEAST as big as your + lead.

Have fun!

^ Yes, I agree, that's the best way to go about getting the current/power requirements.

Edit: Oh and be careful, that's a lot of juice. It will hurt you on a bad day.

Thank you all soo much! I can't appreciate it enough

Edit: No worries. I never turn the power on untilled I am 110% sure everything is hooked up correctly and if I need to make changes I will turn the power off. Luckily my psu has a on/off switch along with a plug

My minor problem was minor after all. Apparently it "was" because i was only using one 12V rail and one ground. I am now using 7/9 12V rails and 4 grounds. Hopefully this should work . I was able to jam my songs at max volume without my psu shutting off or my amp.

I was having an issue when the base was really deep over a certain volume level it would cut my psu off and i would have to re jump the green and black wire.

All fine and dandy now

I'd be weary about using a smaller number of ground wires than your +V wires. Do you have any more ground connectors available to use? If not, you could simply reference your amp to the psu chassis.

Your amp may be "working", but not under the parameters it was designed for. I think an electrical engineer would say that your amp is "struggling" to pull what it needs.

But hey, I don't even know what kind of amp you have, so there's only so much I can determine.

Are you using a class D, design amp? Or it is one of those hybrid amps like the JL slash series?

its a class D amp. I'm pretty sure most if not all of the black wires are grounds. Theres more grounds than 12v rails. I only have less temporarly untill i find kore time to add an 1-1 ratio of 12V/GND

Heres the model of my amp. http://www.bestbuy.com/site/Alpine+...9210874&skuId=8699358&st=alpine amp&cp=1&lp=2

Heres the PSU model. http://www.bestbuy.com/site/Dynex&#...952&skuId=8311052&st=dynex&contract_desc=null

The subs are very old lightning audio models 350W/750W (two subs)

Ah.. that's a nice amp. Keep that one as long as you can!

The only reason left, for your amp appearing to be working, would be that the gain is turned down enough. Its class D, so it very efficient, and should not waste much power via dissipated heat.

What does your PSU say that is available on the +12V rail? There should be a sticker on the side of the PSU that tells...

I still think its being underpowered.

Oh wow, i should have looked there earlier haha. I didn't see they were labeled on the sticker rofl. I looked for like 30 mins online to find labels. "FAIL!"

12V1 (yellow) 14A
12V2 (yellow/black) 15A (I was not sure what those were....)

Not sure if thats the info you wanted

Hmm... you have TWO 12V Rails. If you connect all yellow wires with all yellow/black wires, and reference that all back to the black wires, you should have ~29A available for your amp at 12VDC.

I am no longer convinced that your amp is so underpowered. I forgot that newer PSUs often have two 12V rails instead of one.

The whole dual core, and quad core fad required more 12V current than Pentium IV ever needed.

it was damn difficult getting all 7 in that slot... idk if I can fit 9 haha. Well if you wanna see some photos I might be able to work something out for the help

Just solder all those wires to a single larger gauge wire. I use 10 gauge on my atx conversions. Then you can use a standard car amp "Y" crimp style terminal to connect to the amp very easily.

Oh, good idea. I didnt think i had any 10 gauge wire laying around but i forgot i bought a car kit and i think there is some in there.... i have to locate it though. Well since i have to warm up some lead and all i suppose i can do all this tomorrow. Thanks again for the help! I really appreciate it. I would have been stuck powering it with 1 yellow and 1 black wire had you not helped .

Thanks,
Jeff