Running car amp in house off of PC PSU

[shizzzon 461]

I have been doing lots of searching for detailed information on exactly how this is done and the safety issues wih doing this and have not found anything worth mentioning so let me lay out what i think would work and see what you guys think?

To do so i would assume you would need the following-

PSU with single 12v rail.

PSU with 12v rail output equal or greater than the fuse rating on the amp.

Cut off ALL 12v wires going into connectors and splice them all together to form the rated 12v output ready to connect to Power input on amp.

Do the PSU trick so u can turn on and off the PSU via kill switch in the back.

If all of this is true, then i have a couple questions.

1-

Most PSUs have terrible -12v ground amperage ratings.... is this ok?

Am i suppose to hookup the negative output from the amp to all -12v wiring on the PSU? I do not understand what the -12v amps are for so i am lost on that spec.

2-

What are the safety issues with doing this if it works fine?

Of course an inline fuse will be required but besides that?

I've heard of someone running for a while and the PSU actually set fire. I can assume maybe excessive output to fast but i don't like to speculate about things that might burn the house down, hehe

[///M5 2,833]

Good luck finding an affordable CPU PSU that can supply the power that your amp is going to want to draw. Of course if it is a very small amp, no worries.

[shizzzon 461]

this topic is interesting to research about.

IT is better off saying, good luck finding a bench power supply able to handle the amount of amps a decent amp will draw for the money...

All bench supplies i have seen stop around 55 amps and are over $500. That's too much money for a project.

Now, a company called Silverstone makes very nice PSUs and they just so happen to have a 1,000w PSU with single 12v rail at 80A for $189 after rebate.

That makes for an interesting project if i can find the proper information for doing this and even if it's safe.

[///M5 2,833]

I'd actually expect the Silverstone to do what it is rated to. Check on their specs though as it maybe across a couple different rails or only differential which won't help you power an amplifier.

[coobies5 43]

hmmmm, i think im going to do the same when i have the time and extra change.

[shizzzon 461]

Well, this PSU i am refering to, i'm thinkin about buyin it for my new pc i just built because it only has 1 rail.

They have an article about it somewhere on their site about that PSU and why it's so much better than multi-rails, bla bla bla.

That's what got me thinkin about this.

I just don't understand why a PSU of such magnitude can be so cheap compared to bench supplies.

[JimJ 11]

I just don't understand why a PSU of such magnitude can be so cheap compared to bench supplies.

Well, are you talking about linear or switching supplies? I have a 50A Astron linear supply, and the transformer inside of it nearly gives me a hernia anytime I move it. Good transformers aren't cheap. SMPS designs can be built more cheaply.

[coobies5 43]

yeah, the transformer in my ps for my 7.1 computer speakers weighs a good 10+ lbs and it just fits in the palm of my hand.

[lithium 358]

i think i saw someone use 3 psu's 5v rails together...

[mdexxxiv 1]

You would be better off with a motorhome power inverter. Some of these convert 110V into 12V @ 40 amps or something like that. It depends on what type you get. These can be found at any RV repair shop for under $200.

[binil 0]

I have been doing lots of searching for detailed information on exactly how this is done and the safety issues wih doing this and have not found anything worth mentioning so let me lay out what i think would work and see what you guys think?

To do so i would assume you would need the following-

PSU with single 12v rail.

PSU with 12v rail output equal or greater than the fuse rating on the amp.

Cut off ALL 12v wires going into connectors and splice them all together to form the rated 12v output ready to connect to Power input on amp.

Do the PSU trick so u can turn on and off the PSU via kill switch in the back.

If all of this is true, then i have a couple questions.

1-

Most PSUs have terrible -12v ground amperage ratings.... is this ok?

Am i suppose to hookup the negative output from the amp to all -12v wiring on the PSU? I do not understand what the -12v amps are for so i am lost on that spec.

2-

What are the safety issues with doing this if it works fine?

Of course an inline fuse will be required but besides that?

I've heard of someone running for a while and the PSU actually set fire. I can assume maybe excessive output to fast but i don't like to speculate about things that might burn the house down, hehe

My Electronics is pretty buggy at the moment. But I will tell you what I know.

Its ok to run your Amp from a PC PSU (SPMS) - but you need to kind the right kind of Amp and SMPS. Your Amp should not use dual power supply (+12V, 0V, -12V).. because as you pointed out -12V in PC SMPS is not having enough Ampheres to power your Amplifier. The -12 V in SMPS is used for serial communication in PC's as far as I know. So if you use -12V, expect the SMPS to catch fire..

But if your Amplifier uses only +12V and GND (ground), you might be in luck.. Most SMPS available today could have enogh juice to power your Amplifier..

You should know that this is an option if you have a spare PC SMPS.. If you are buying a new SMPS, you could buy a SMPS specialized for your Amplifier...

[efxtruck 0]

I have been doing lots of searching for detailed information on exactly how this is done and the safety issues wih doing this and have not found anything worth mentioning so let me lay out what i think would work and see what you guys think?

To do so i would assume you would need the following-

PSU with single 12v rail.

PSU with 12v rail output equal or greater than the fuse rating on the amp.

Cut off ALL 12v wires going into connectors and splice them all together to form the rated 12v output ready to connect to Power input on amp.

Do the PSU trick so u can turn on and off the PSU via kill switch in the back.

If all of this is true, then i have a couple questions.

1-

Most PSUs have terrible -12v ground amperage ratings.... is this ok?

Am i suppose to hookup the negative output from the amp to all -12v wiring on the PSU? I do not understand what the -12v amps are for so i am lost on that spec.

2-

What are the safety issues with doing this if it works fine?

Of course an inline fuse will be required but besides that?

I've heard of someone running for a while and the PSU actually set fire. I can assume maybe excessive output to fast but i don't like to speculate about things that might burn the house down, hehe

Did you ever think to get a 120V to 12V converter like they use in demo boards?????

[shizzzon 461]

yea i did but look at how much they are for 200A continuous... thats if u can even find one that powerful.

[Sniper 0]

your best bet is to use more than one power supply. its gonna be hard as hell to find 50+Amps @ 12V with any power supply.

[Kent535 25]

Will Take A look At This Later:)

[weehascootchy 0]

Simple.

Get a PSU with a great amp rating for your amplifier

using the four pronged connecter (see picture) mostly used for older CD players inside a computer, cut the red wire (+) the black (gnd) and then cut the second black wire so that you have a 2" long wire by itself

Red wire obviously goes into your power input

Black into the ground

now with the 2" wire you cut, bridge the positive input with the RMT (remote) input on your car amp

your car amp turns on when it gets a jump off of a car battery so when you turn on your PSU it thinks its hooked up into a car and activates

thats about it

MAKE SURE: wrap open end wires with electrical tape

Also, I just read that the yellow wire provides more voltage but im not sure.

I've done this before and it worked out fine I just can't re-find the article, so bitch at me if you need it because I know my instructions here aren't that thorough

[inkfx 3]

Also, I just read that the yellow wire provides more voltage but im not sure.

I know when wiring computer fans you can change the voltage by switching up the wires.

12v

7v

5v

Don't plan on running a lot of power off of a PC PSU. The absolute most you're going to see amperage wise is around 80amps on the 12v+ rail. You can pick up a PSU with a 60amp 12v+ rail for around $130-150 shipped (or cheaper if you can find a deal, which are usually frequent with instant rebates or mail in rebates).

Edited December 4, 2009 by inkfx

[weehascootchy 0]

I know when wiring computer fans you can change the voltage by switching up the wires.

So in this case it doesn't matter?

Unless you can find a single amp that can take 17volts

powering multiple amps with one PSU won't work out anyways.

Stick with the red wire as your + input.

[johnecon2001 82]

This is a horrible idea. There's a reason there are home audio amplifiers. There's also a reason people make 12v power supplies ment to take the type of abuse we're talking about here.