# How to hook a car amp up to your PC



## hellrazor (Feb 25, 2010)

Do you have a car amp laying around? Are your gaming experiences too.... quiet? Do you have crappy-ass Durabrand PC speakers that snap, crackle, AND pop? Do you get the itch to wake up your neighbors?

If you answered yes to any 2 of these questions, this guide may be for *you*!

Ok, enough of the cheesy advertising. I've had this one done for a while, so I can guarantee if you do it right (and every part works), that it should all be fine and dandy.

*Things you'll need:*

1 x Car Amp
2 x Box Speakers
1 x Minijack-to-RCA cable
Some x Various other wires and cables
Various x Tools
A x PC

*Knowledge You'll need:*
A 200 watt car amp DOES NOT pull 200 watts (that would mean my entire PC is running off 50 watts) - I'm not sure what it does pull though, so don't ask.

A car battery gives 12 volts, so does your PSU.

If your doing this with an independent PSU (AKA, not the one in your PC), you'll need to connect wires 15 & 16 (green and the black right next to it) to get your PSU to turn on. I'd also recommend getting one with a rocker switch in the back, so you don't have to rig one in between 15 & 16.

If your amp uses more than around 500 watts you'll want to use multiple molex connectors, because a single 14-gauge wire might not be able to hold all the charge needed for the entire amp, causing it to heat up and possibly melt. There is a method to the madness; if you unplug all your drives and your video card, you should be able trace all the wires back to 2 or 3 bunches (unless you have a modular PSU, in which I'm not sure how this would work), you'll want to connect the amp to as many bunches as you can. This way you're effectively dividing the charge on each wire (and sometimes making it easier on your PSU), if it works correctly. If you do two (or more) connectors on a particular bunch, your not gaining much because the charge will still have to go through the single wires that come out of the PSU, which is what you're trying to avoid in the first place.

*Step 1: Prep your PC*
Turn down the volume on the taskbar, and I mean DOWN to like 2-10%. Remove your side panel (unless your using an independent PSU)

*Step 2: Wiring up The Amp*
Connect the red wire (Positive) to the orange wire (Remote). Make sure that there's just bare wire at the end of all of the wires coming from your amp.

Grab a Molex connector, you want the male end. Cut the Yellow (+12v DC) and the Black (-12v DC) right next to it, you'll want them as long as you can get (you can also remove the red and black if you want, but when I did it the Yellow and Black got a little shaky/loose).

Connect the Molex's Yellow to The Amp's Red & Orange, connect the Molex's Black to the Amp's Black. Twist, tie, tape.

*Step 3: Connecting the Amp and Speakers*
You want box speakers (the ones that just have the - and + wires hanging out the back), if you don't have any you could try Goodwill (you can usually get them for like $20 over there). Connect them to The Amp. I'm not sure whether the - on the speakers _really_ needs to be connected to the - on The Amp, but do it just to be safe (my speakers just have 2 nondescript wires, and they work fine). You may need to make them longer too.

*Step 4: Connecting it to your PC*
Plug the male Molex into your PSU, grab the minijack-to-RCA and plug the minijack into your sound card with the RCA connected to The Amp. If you have an amp that has more than 2 channels, you may need to move the speakers and RCA cables around to get the right ones.

*Step 5: Fine tuning*
Make sure all the wires are insulated good. Check them again. The last thing you want is your house up in flames, so check them once more.

If your using an independent PSU, make sure it's plugged in.

Turn on your PC. Adjust volume as needed (I did this with a 200 watt amp, and mines at 4% volume).

*Step 6: Make sure it's all up to par*
Play a game, more specifically, a really power-hungry one *cough* Bioshock 2 *cough*. Make sure your PSU is fine and running good.

*Other remarks:*
You could also hook up a car radio to your PC if you'd like, but I haven't done it yet so I don't have a guide.

If your case is a tank (really heavy-like) you could rig up The Amp to your right-side panel, but mine's a lightweight, so again, no guide.

If your using an independant PSU, you might want to remove unnecessary wires. I cannot recommend this as your PSU could deep-fry your    pasty-white nerdy ass any day of the week. PSU vs. You = Dead You (and possibly cops). I have done this though (rigging it up for a friend ), so I won't say it's impossible.

YOU MAY NEED TO ADJUST YOUR BASE. It'll probably be overwhelming. Try adjusting the gain on The Amp first, then adjust the equalizer in your drivers/programs next.

IF YOUR AMP NEEDS A CAPACITOR don't ask me, I don't know what to do with it or how to rig it or charge it or do anything with it. Mine doesn't need one, so no guide.


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## MKmods (Feb 25, 2010)

this would be a fun mod to do, making a case with a quality amp , head unit, separates with sub. (maybe even throw in a headphone amp)

Be careful when using a car amp and a comp PS, very few comp PSs are able to supply as much current as a good amp needs. So make sure to do your homework (my car amp can use up to 100A) So its important to know how many amps your stereo amp pulls (dont pay as much attention to the amount of advertised watts as on most car stereo amps thats misleading)

and most likely you will need to run several yellow wires(grounds too) off your PS together to supply the current.


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## Zebeon (Feb 25, 2010)

that is awsome!!

but like MK said.. BE CAREFUL or you will burn something up.
My amp pulls LOTS of power


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## TVman (Feb 25, 2010)

no pics


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## theonedub (Feb 26, 2010)

You need thicker gauge wire to prevent burning or melting, the min I run even for a 200 watt amp is 8ga from the battery to the amp. This really has bad idea written all over it in terms of safety.


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## cdawall (Feb 26, 2010)

this will only work with low watt amps my car amps will smoke any current PSU...


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## Papahyooie (Feb 26, 2010)

I thought this was going to be a thread asking how to hook up a car amp to household speakers. A big no-no of course. I was pleasently surprised to see a nicely put together guide for something that is useful and actually works the way it is meant to, and by someone who's done his homework no less. Something that could be mentioned is gauge of wires needed. Too thin wires could be bad for business. Other than that, Kudos!

D'oh dub beat me to it. And as CDawall says, only very low wattage amps. 2000w kickers will NOT work for this lol.


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## selway89 (Feb 26, 2010)

I would NOT recommend using the PSU to power BOTH the amp and pc. You could take the whole lot with it! A separate PSU with a large current rating on the 12V rail. 

I have a home made sub-woofer using a car amp to power it with my hifi speakers. I measured the current that my amp drew at the volume I would be listening at and checked the PSU could deliver. I should ideally change the fuse on the amp to the rating of the 12v rail or less but haven't got round to it.
And as others have mentioned fatter wire is needed to ensure no wires burn up! I removed all the un-used cables from the PSU and combined all +12v and GND to build up the thickness to take the current.

On a side note I personally don't like the sound of car speakers. I have always and will prefer proper HiFi equipment, I am only using a car amp for the sub as it has the functions I need and was dirt cheap. 

I may have pics for guidance somewhere.


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## cdawall (Feb 26, 2010)

Papahyooie said:


> I thought this was going to be a thread asking how to hook up a car amp to household speakers. A big no-no of course. I was pleasently surprised to see a nicely put together guide for something that is useful and actually works the way it is meant to, and by someone who's done his homework no less. Something that could be mentioned is gauge of wires needed. Too thin wires could be bad for business. Other than that, Kudos!
> 
> D'oh dub beat me to it. And as CDawall says, only very low wattage amps. 2000w kickers will NOT work for this lol.



my pair of 600w rockford fosgate class A/B's wont do it either...


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## theonedub (Feb 26, 2010)

Selway89 has a much more sound attack plan. The way the OP explains it he has one 14ga (if that) wire supplying power to the amp- bad idea. 

My A/B Fosgate is strong but is the poster child of inefficiency, if I pushed my stereo often in my car it would be replaced my a class D in a heartbeat (powers my Premier sub only) /OT


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## hellrazor (Feb 26, 2010)

TVman said:


> no pics



No camera.



theonedub said:


> You need thicker gauge wire to prevent burning or melting, the min I run even for a 200 watt amp is 8ga from the battery to the amp. This really has bad idea written all over it in terms of safety.



Mine works fine with normal Molex wire (and whatever gauge is on the amp). I haven't done any real tests with it yet though (I live in an apartment complex, and I DON'T want to wake the neighbors). It's probably a good idea, but the only way to get the full benefits from doing that is to replace the wire inside the PSU, which is NOT a good idea.



MKmods said:


> this would be a fun mod to do, making a case with a quality amp , head unit, separates with sub. (maybe even throw in a headphone amp)
> 
> Be careful when using a car amp and a comp PS, very few comp PSs are able to supply as much current as a good amp needs. So make sure to do your homework (my car amp can use up to 100A) So its important to know how many amps your stereo amp pulls (dont pay as much attention to the amount of advertised watts as on most car stereo amps thats misleading)
> 
> and most likely you will need to run several yellow wires(grounds too) off your PS together to supply the current.



Same as above. I've rigged this with an indie-PSU for a friend and the PSU in my PC for me (I don't have PSUs laying around like he does). Mine hasn't ever gotten really loud, so unless you're throwing a party or so, it should be fine.

I did, however, plug an old kitchen-counter style radio into his, and saw how loud it could go. I was pleasantly surprised, it started fluttering before it the radio maxed out. No fires, no sparks, it might have gotten warm though (I used liquid tape on his, and that stuff never seals right the first time, so I wasn't in a hurry to go check it out - and *yes* he did retape it after I was done and left).

Also, the comment about the "crappy-ass Durabrand PC speakers that snap, crackle, AND pop" at the top was my reason for doing the whole thing in the first place - and believe me, it was *very* well justified. They sounded like a 50 year old record player, and only got worse when I moved the mouse (or did anything else, for that matter).


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## cdawall (Feb 26, 2010)

theonedub said:


> Selway89 has a much more sound attack plan. The way the OP explains it he has one 14ga (if that) wire supplying power to the amp- bad idea.
> 
> My A/B Fosgate is strong but is the poster child of inefficiency, if I pushed my stereo often in my car it would be replaced my a class D in a heartbeat (powers my Premier sub only) /OT



i have my fosgates powering a alpine type E 10" each in a slot port box i have peaked both the subs but not the amps hehe. great amps IMO who needs class D's these hit harder than any other similar class D setup i have heard


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## theonedub (Feb 26, 2010)

little more OT  

Fosgate amps are indeed very nice. I had bought a Hifonics 1206D that I used for a short time, but was more satisfied with my P5002. My situation is reversed though, I have mine powering a Premier TS-W3002SPL slot ported to ~36hz- peaked the amp not the sub.


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## Lazzer408 (Feb 26, 2010)

Will this help? Note the green ps-on terminal for both 20 and 24pin ATX connectors. Green wire on either.

As far as the math. If a 12v rail can supply 20a then 12*20=240w. Amplifiers are about 65%(Class-AB) to 90%(Class-D) efficient. 

Derated Class-AB 240w*65%=156watts/2ch=78w per channel
-or-
Derated Class-D 240w*90%=216watts/2ch=108w per channel.


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## hellrazor (Feb 26, 2010)

Yeah, that's really good. Thanks!


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## theonedub (Mar 1, 2010)

Lazzer408 said:


> Will this help? Note the green ps-on terminal for both 20 and 24pin ATX connectors. Green wire on either.
> 
> As far as the math. If a 12v rail can supply 20a then 12*20=240w. Amplifiers are about 65%(Class-AB) to 90%(Class-D) efficient.
> 
> ...



I hate to bump this, but it is relevant. That's not how efficiency works for a car amplifier. If you have an amp rated for 240w that has an efficiency of 50% its going to draw 480w to produce the 240w and waste the other 240w in heat. Its just like efficiency in a computer PSU- a 700w PSU that is 80% efficient will supply the 700w, but it will consume over 700w in order to do so. The rest is thrown away in heat. 

It changes your numbers around by a substantial margin.


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## assaulter_99 (Mar 1, 2010)

Ah so you posted it here! rofl! I commented bout that in another thread earlier. Thats cool man, I might give it a run this week end. I have a couple of car stuff lying around.


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## dr emulator (madmax) (Mar 1, 2010)

ha ha i did this years ago when someone bought a car tape player around, so i wired it up to my snes and had it in my shed /workshop/room ahh the joys of not having anyone near enough to moan about the noise  

@Lazzer408 where's the diode on that relay man :shadedshu

also another consideration is that unless you have an ultra stable psu your likely to have the the psu cut out because of big variations in the amount of current drawn


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## Lazzer408 (Mar 1, 2010)

dr emulator (madmax) said:


> ha ha i did this years ago when someone bought a car tape player around, so i wired it up to my snes and had it in my shed /workshop/room ahh the joys of not having anyone near enough to moan about the noise
> 
> @Lazzer408 where's the diode on that relay man :shadedshu
> 
> also another consideration is that unless you have an ultra stable psu your likely to have the the psu cut out because of big variations in the amount of current drawn



It's in the other schematic I posted weeks ago when the last guy asked how to do this.


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## dr emulator (madmax) (Mar 1, 2010)

just pullin your leg


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## Lazzer408 (Mar 1, 2010)

dr emulator (madmax) said:


> just pullin your leg



I figure but I did update the schematic and slapped in a diode.


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## SabreWulf69 (Mar 2, 2010)

Lol, I've done this before, completely impractical though. Had an old Dell server board with dual independent 750Watt PSU's connected to it, with a lot of Amperage and it still distorted more than when I simply had a car battery hooked up to it. Dangerous, need thick cabling, and a lot of power, DO NOT put car battery in your room if you were thinking about it either, as the amount of amperage in them is enough to weld a spanner across the terminals. The only safe way to do this I found is to get an expensive adjustable DC power supply with at least 120+ Amps of power, or buy proper home theater gear, that isn't designed in any means for weather durability, just quality with the higher end stuff. PSU's are simply NOT designed to supply enormous amounts of current draw on and off all the time, that any decent car amplifier will require.


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## Lazzer408 (Mar 4, 2010)

Post #14 I explained that.


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## Lazzer408 (Mar 4, 2010)

theonedub said:


> I hate to bump this, but it is relevant. That's not how efficiency works for a car amplifier. If you have an amp rated for 240w that has an efficiency of 50% its going to draw 480w to produce the 240w and waste the other 240w in heat. Its just like efficiency in a computer PSU- a 700w PSU that is 80% efficient will supply the 700w, but it will consume over 700w in order to do so. The rest is thrown away in heat.
> 
> It changes your numbers around by a substantial margin.



Read it again. You basically just repeated what I said but I based my amps 'rating' off available power and when the efficiency of the amp is taken into consideration that power becomes alot less.


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## LDorn920 (May 17, 2010)

hellrazor said:


> Do you have a car amp laying around? Are your gaming experiences too.... quiet? Do you have crappy-ass Durabrand PC speakers that snap, crackle, AND pop? Do you get the itch to wake up your neighbors?
> 
> If you answered yes to any 2 of these questions, this guide may be for *you*!
> 
> ...



Hello! What about Just having the amp Hooked to a Car(or Large MotorCycle)Battery, but have the Mini-Plug from the PC to the amp! That would sove the Power consumtion Problem, with out putting a strain on your PC!
This is a Very Good Idea! Minds Are at Work out there! Thanks for the tips!


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## hellrazor (May 17, 2010)

Because the battery would die, and then you'd have to recharge it again.
That, and batteries never turn off, so you'd probably end up frying yourself a good one.


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## LDorn920 (May 17, 2010)

hellrazor said:


> Because the battery would die, and then you'd have to recharge it again.
> That, and batteries never turn off, so you'd probably end up frying yourself a good one.



But, there is no danger of shock from a 12V Battery! I hook amps up in the house all of the time(Daily)! And My Battery Charger Keeps the Battery Charged!  I only have to put the Charger on, once or twice a week! Depending on the types of amps and how much I used it!
Again! I am Glad that There are Minds at work and Thanks for your reply!


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## TechnicalFreak (May 17, 2010)

I actually tried this once, but not with the PSU from a computer, but a standalone powersupply.
It was the most stupid thing I could have done, the cable actually started to melt at the end.

I think that's the reason the cable from my amp to the battery was like 5x thicker and had a big fuse aswell.

But now, I found a better way. I just connect my PC to the AUX in on my stereo - damn that's loud!


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## BazookaJoe (May 17, 2010)

I've been using PSU's in parallel with a car battery to power car amp's on PC's for years - works great if you do it right.

Just don't get STUPID with the amp. Even something as small as a 300 Watt car amp can make more noise than the rest of the ppl in your house could ever reasonably tolerate If you pick your speakers carefully and correctly.

Edit : I now make my own In-Line PSU's to run the amp and the battery simultaneously - See a pic here : http://forums.techpowerup.com/showthread.php?p=1846211#post1846211

Not directly Related : One of my very early works in Home PC Audio advancement using Car Amps 

This was fun, but a prime example of Doing It Wrong.


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## SabreWulf69 (May 18, 2010)

Some good information to also follow can be found from --> http://forum.ecoustics.com/bbs/messages/4/17571.html


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