Car Amplifier and Subwoofer Powered by a Computer Power Supply

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Introduction: Car Amplifier and Subwoofer Powered by a Computer Power Supply

Background Information:

For starters, your car amplifier is meant to receive its voltage from a 12 volt DC source which is your car battery. Common households use approximately 120 volts AC. So you can see that we two problems. The first is that we need 12v and not 120v, if this was the only problem it wouldn't too hard to solve. However the real problem is that we need DC electricity instead of AC. So why not use a simple transformer, like a cheap laptop charger that supplies 12v DC?

The problem with using some type of transformer is not that it puts out 12v but its the amperage. A typical car amplifier requires anywhere from 10-30 amps. (You can check how much amperage you need by looking at the fuses usually located close to the inputs on your amplifier.) So if you were to use a simple transformer that delivered 12v DV, it would most likely work at very low volume but it would get destroyed by the power needs once the volume starts to get louder and the amplifier requires more amperage. So, do they make transfers at a high amperage at 12v DC?

Yes, but they are often very expensive, easily on the upwards of a few hundred bucks for a quality one. So what's the best solution thats also more economical?

The best solution is to convert a computer power supply (CPS) to work at 12v DC and deliver high amounts of amperage. This is the most effective and possibly also the simplest way to get your amplifier working at full capacity. The process isn't too complex, it would be beneficial to have some knowledge of basic electronics and circuitry, and also be able to solder.

Tutorial:

To begin, first know how many amps your amplifier needs. Do this by looking online or checking the fuses on your amp. Ideally you would want to exceed the amperage on the fuse so that your not constantly working the CPS too hard. This is the one i used, its rated at 24 amps for the 12v output. (http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2475867&CatId=1078) Once you have your CPS, search the serial number with additional words such as pinout to locate your models pinout sheet. Its typically not too hard to find pinouts of a CPS. Once located, you want to find the pin that says something like "PS_ON" or "PS_OK", typically located on the "Main Power Connector" plug. Most of the time the wire will be green but I have seen a few that have been purple or other different colors (typically older power supplies don't use green). Once you've located that wire, connect it to any of the black ground wires. What this does is allows the CPS to turn on properly. So once you've connected these two wires, try to turn on your CPSband it should work.

Now that you have your CPS working, unplug it and take the cover off. The orange wires usually supply 3.3v (good for wiring any LEDs if you want) and the red wires usually supply the 5v source, both in DC voltage of course. If your only using the CPS to power your amplifier, then trim all the orange and red wires. KEEP the Yellow and Black wires, those are the ones used to supply the voltage and ground the amplifier. Once down, group all the yellow and black together separately. I used zip ties so they weren't a mess.

I STRESS that it is needed to wire all the yellow wires and all the black wires to the amplifier. When running this high of voltage, just one or a few wires going to the amp may work great at first but it will lead to problems. Think about the wire thats used to connect the amplifier to your car battery, those wires are thick. Its not only a strong fire hazard but also keeps the voltage flow more open and puts less stress on the amplifier by wiring them all together.

Now you need to find a way to attach a bundle of wires to a small terminal on your amp. The best solution i found was to use a fork wire terminal for two reasons. (1) it makes a great connection. (2) it doesn't look sloppy. You can buy these at your local hardware store, automotive store and just about anywhere that has a hardware section. I would encourage you to solder the wires together into a bundle before crimping to terminal on. This ensures that every wire is connected and makes it hard to pull the wires out from the terminal. For extra precaution i heat shrinked the connection as well.

Additionally, you will want to bridge a wire from the 12v source on your amp to the "REM" or "REMOTE" terminal on your amplifier as well. This bridge allows the amplifier to turn on.
So connect the 12v, ground and REM wires to your amp and it should be good to turn on. Don't connect it to your subwoofer right away though.

Lastly, im sure you know how to connect your amplifier to your subwoofer but you need to know how to connect it to your stereo. This is a little complicated because of the amount of ohms your amplifier receives and the amount of ohms your stereo puts out. It almost all cases, your home stereo receiver will put out a 8ohm signal and your amplifier will require a 4ohm signal. This problemcan be easily solved by using the speaker level inputs on your car amplifier. Simply connect both channels of the speaker level inputs on your amplifier to just one pair of terminals on the back of your receiver. This splits one 8ohm signal into two even 4ohm signals for your amplifier. Double check your ohm ratings to be sure though.

Now, give it a try.

Additional Information:

Be careful, electronics can be fragile in the right environment and you don't want to damage something and spend hours or maybe days trouble shooting or having to re-buy something. There's no shame in posting a comment if your unclear about something and need help.

I have had offers to build the CPS unit already converted and ready to hook up. I have no problem doing this for a bit extra than what it costs for materials and shipping. Send me an email to work something out.

6 People Made This Project!

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116 Discussions

0
RitcheboyB
RitcheboyB

Question 1 year ago on Introduction

if computer power supply use in audio amp the cps is have a high frequency it does affect the amplifier out like it will cause distortion or noise at the output of an amplfier

0
Snelo
Snelo

Answer 2 months ago

Nope,, the problem is that you put too much gain in your amplifier,,,, which is not a volume,

0
ChrisH841
ChrisH841

Question 1 year ago on Introduction

I am powering my amp with a car battery Charger but I can only have it at a certain level or it starts to break up and my power light starts to dim or sometimes shut off when the bass hits now it's not going into protect mode when it shuts off which leads me to believe it isn't receiving enough power so I switch it to START and it hits a few times real good then the charger clicks off.. I've been stuck on this for 2weeks now.. What can I do.. I have power supplies mother boards excites but not sure if there big enough to power a AC2600.2 amp and a RZR1-2500 class d am..

0
Snelo
Snelo

Answer 2 months ago

Just buy 2 cps and do the above trick,,, keep both gains in your amplifier low, you will be fine

0
Djmaaney
Djmaaney

Question 1 year ago on Introduction

I have 3x 20amp fuses on my amplifier. Will this amplifier require 20amp or 60amp power supply?
Thanks

0
Snelo
Snelo

Answer 2 months ago

Nope, even 20 is fine,, remember the gain on your amplifier is not a volume,, just find the right spot where your amplifier doesn't have a humming sound

0
Snelo
Snelo

2 months ago

Hi guys, my question is can I connect 2 computer power supplies on 1 amplifier?

0
Kutkowboy316
Kutkowboy316

8 months ago on Introduction

I have tried the smaller cps from a dell. I retired it for the use of abelcom sp382-ts. I have 1 that runs a car headunit and also a 500watt 2 ohm 2 channel amp. However the problem you haven't mentioned: current overload. Even on a smaller amp a cps will shut down from overdraw. The cps has to be opened up and the dead cycle timer bypassed. Several videos on YouTube show how to do this simple process. I have been unable to figure out how to open my supply however as it is a server power supply that i hacked

0
Smitty4229
Smitty4229

Question 10 months ago on Introduction

Is it necessary to use an ampler that can be bridged or is it possible to use one without the capability to do hat?

0
ShishankS1
ShishankS1

Question 1 year ago on Introduction

If I use corsair 450w psu....
Then it it ll be nice for me or it may doesn't do well with that

0
RanjithK57
RanjithK57

Question 1 year ago on Introduction

My Sony xplod 500 watt 12 volt DC 16 Ampier fuse but I need to know about what Ampier needs to work Perfect sounds

0
ddvniek
ddvniek

9 years ago on Introduction

Hi. I have recently hooked up my Amplifier to a PCU. But I only used one black and one yellow wire of the PCU to power it. You said to connect all the yellow wires to each other and all the black wires to each other, and to use them that way. But when I asked if I must connect the yellow and black wires together (Like you did) on Yahoo Answers, people told me I will blow my amp and PCU if I did that. Why I don't know.... Can you please tell me if I will blow it or not.
My PCU supply's 14A on 12V+
It's a 450W
Please help

0
eh1080
eh1080

Reply 9 years ago on Introduction

Thats a great question. After some additional research, it appears that the standard wire size for a computer power supply is 18awg. According to various sources, it seems that 16A would be the maximum for an 18awg wire.

However, there is a lot of information that skews this 16A rating. Each situation has their own variables that need to be considered specifically for that application.

Personally, i have had this set up for about two years now and use it daily. I've also built many more of these conversions and have never had or heard of any problems.

This question leads me to wonder why the power cable in your car for an additional amplifier is so huge (like 4-8awg). It just doesn't add up to me, why you would be able to use an 18awg wire in your house and then have to use something like a 4awg wire in your car.

Theres clearly something i'm missing here, ill keep doing some research in my down time and see if i can figure this out.

0
Ilikeaudio
Ilikeaudio

Reply 5 years ago

Hey, a question, if u have two 25a fuses on a four channel sony xplod 500 watt xm-504z, would u have to get a power supply to equal both fuses or just one? I want to bridge a 10" 300 watt sub and connect two speakers, how much amperage would i need, equal one fuse or both?

0
Mcalexander475
Mcalexander475

Reply 1 year ago

No. A 25a fuse will blow at about 28-30a. A circuit is normally only 80% of the total amps of the fuse. Two 25a fuses are still only 25a

0
Ilikeaudio
Ilikeaudio

Reply 5 years ago

Im looking at this psu, what do u think? http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=8438086&CatId=1079

0
GuillaumeP32
GuillaumeP32

Reply 1 year ago

Would get a specialized one or take old one removed from computer

0
GuillaumeP32
GuillaumeP32

Reply 1 year ago

I would go for a little more than the fuses value