Wiring a car amplifier and headunit up indoors

proud to be the first on instructables regarding HU's
im gonna show you how to wire up a car amplifier and headunit in your house without the need for a battery and charger.
This instructable will allow you to wire in the following configurations:
Amp and headunit steps 1-6
Only the amp steps 1-4
Only the headunit steps 2, 5-6

make sure you have a power supply unit that matches or is as close to the max output in watts as your amp is, you dont want your amp to burn out, i know that the Amperes(?) are important too but i dont know much bout them so... .

IMPORTANT!! dont be a idiot, turn your power supply unit off and disconnect it from the mains when your working with the cables. ALSO im not responsible for any damages incurred.

ive only seen one other instructable on doing this, but they didnt cover the headunit part of the build. the person was Br14n and a link is in one of the steps.

a video :D
http://www.youtube.com/watch?v=xI3s7F36E4c

please let me know what you think

Step 1 You will need..

You will need...

a PSU (power supply unit) from a PC or XBOX,
wire cutters
a car amplifier
a headunit

Comments

[trees415]

Yeah, I was going to say, this is not a great idea, since it will work for 5-10 minutes,then the 12v rails will literally melt. Its just too much load on the 12V rails (16awg), thus you will get a huge drop in voltage and it will be way less then the required 300 mills per ampere. For example, supping an amp requiring 800 watts with power via a 1-2ft 16 gauge wire at 12 volts will result in a .71 voltage drop, and 29.2 mills per amp. While you could shorten the wire to 3 inches to take care of the voltage drop, your mills per amp will stay the same, thus it will not supply nearly enough power.
The only way this could be even remotely possible would be if you were able to use at least 32 molex 12v wires (16 AWG) for the battery and at least 32 Molex Ground wires to ground it, although I might be wrong on the ground part. However, even this is nearly impossible to do.

[badbradmx]

5-10 minutes? nah, ive had it on all day watching films playing music and games. i know this isnt the best way to do it, the best would be to have a car battery in your room which will always need charging. so you know most of what you said didnt really make sense, i can however peice it together.

[yamaha_dodge]

A computer PSU does not supply enough amps to the actual audio amplifier. Look at the size of the wire you would use if this was in a car. Now it will turn on and everything but if you make the audio amp crank sound with heavy base. You will do one of a few things. 1 the wires from the psu will melt and short circuit. Or the psu fries itself and could catch fire or wreck your amp / head unit.

[badbradmx]

i know. its a temporary thing, this is going in my car, at some point, its all money issues at the moment, until i can afford to make a decent home theatre system this will do. besides i cant crank it up, not allowed, damn parents haha. your lucky to catch me, first time ive signed in in like 4 months lol.

[bigjoe09]

hi can i ask what wattage  PSU will i need ? thanks . joe

[badbradmx]

research your amp, find out what amperage it draws and match the psu to that, mine draws 21A max but my psu outputs 8A so i need a more powerful one

[Blackice504]

People this is a nice idea i had my amps setup like this for years but i am sure all people who have done this have notice a HUM from Subs i have two car amps running from 3 PSU to get the amps to work at full power. and there was a hum why? i can tell you why switch mode psu put out noise in the DC sure there is a loot of chokes and Inductors and caps to get most of it out but its still some there and on thinings like AMPS especialy 400watts + ( RMS ) NOT PMPO junk you will get a lot of hum when there is no music and the fact that its there with no music means it is there with music you just do not hear it but your amp is still wasting all that power on hummmmmmm so solution wait till you find a dead microwave oven take the Transfomer from it then make your PSU from that. i will be writing a instructable on this soon. if some are not sure how. and yes its specialy for CAR amps,

[badbradmx]

i havnt noticed the humming but i rarely go loud enuough for the power the humming uses to be noticeable. if you wouldn't mind posting a link to the instructable your talking about making to me, because id like to remove the humming even tho i havnt noticed it, but i will notice it now because you've told me about it haha. not to mention i wanna use the computer my PSU was swiped from and my cuz is gonna be getting rid of an old microwave soon, so perfect situation. i have a plan to improve the looks even more by completeling the box and and having everything enclosed and hidden :D

[Blackice504]

its just a hum when you have the amp on its a single wave tone some people may not notice it but if you feel the speaker it will be buzzing away but true you need the amp up to be able to hear this i have mine set on one volume and the computer controls them i will try to make a instructable soon as i get a new microwave to kill. oh i mean recycle opps. lol

[badbradmx]

haha kl, well of course i had to check it and it does hum i just figured it was the PSU fan before and i do the same, the main windows volume bar doesnt go beyond 20, ever, normally at 6. well when u do get the chance dont forget about me :) because the humming is gonna annoy me that i know its there :/ lol

[Blackice504]

and sorry i forgot to say very clean work on your amp i left mine well just Functional ( only tech heads would like its looks because of big huge wires everywhere ). but not a fan of anything Sony only there Sony Monitors where good.

[sk8inwendizendi]

http://www.youtube.com/watch?v=ktc-m8qT32s

[sk8inwendizendi]

i dont understand, when i hook it up like shown in my last pictures, the PSU turns on but HU does not. When i connect a ground from HU and ground from PSU the PSU does not turn on.

[badbradmx]

can u post pics of how your ground is connected to both the PSU and HU please, by the way, are you able to run an amp? As you dont need the HU but i can understand if you want it

[sk8inwendizendi]

ok theres 2 pictures with labels.

http://i36.photobucket.com/albums/e14/eSsk8er14x/powersupply.jpg

http://i36.photobucket.com/albums/e14/eSsk8er14x/headunit.jpg

[badbradmx]

ye read my last comment and connect your ground (Y) thats it, after that it should work

[sk8inwendizendi]

this is what i have so far and its not working. what am i missin?

http://i36.photobucket.com/albums/e14/eSsk8er14x/wiring-1.jpg

[badbradmx]

right ok, that was a bit of a dodgy diagram lol. but i think i see what your missing, that is your ground, look at the fouth pic, it shows that i have used a green and yellow cable that runs from the GND on the PSU connector to (look at third pic (maybe i should rearrange the pics lol)) the GND on the HU. i know its difficult to see but i have tried to highlight it. i dont know if your is the same but the GND on the HU is the only black cable. let me know how you get on, if it still doesnt work then post some pics of the setup itself , the more detailed you are with the pics the easier i can identify the problem.

[sk8inwendizendi]

ok, im pretty clueless with this all but just stick with me a little while longer. When u say connect the ground are you saying connecting a ground wire from the HU and PSU together? thanks guys

[badbradmx]

connect a wire from the ground on the HU to the ground from the PSU so pretty much the answer is yes haha

[sk8inwendizendi]

i did this and my HU doesnt turn on :(

[badbradmx]

ok, does your PSU turn on? have you connected all the cables, ACC, LIVE and live from your PSU? one last thing, have you connected your ground? if you answered yes to everything then i dunno why it wont work, maybe you need a more power PSU :/

[sk8inwendizendi]

its me again :) soooo blue from PSU, yellow and red from HU all together? I know it should be obvious from the picture but just checkin, i want to do this right. thanks

[badbradmx]

ye, but your colours could be different, make sure your using the ACC, LIVE and a live from your PSU, then your GND obviously lol

[sk8inwendizendi]

thank a lot for the help. let me know when u figure out the speaker wiring

[sk8inwendizendi]

so simply cut the two wires and connect them to eachother?

[badbradmx]

if u dont mind cutting the cables then yes, and ive only just noticed the massively bad typing in the info boxes lol

[sk8inwendizendi]

what kind of wire did u use to bridge them? please comment back thanks!

[badbradmx]

just a random piece of excess wire, was speaker wire i think

[stuuf]

Does your power supply actually have enough 12V current to run the amp? Most of the ones I've seen only output a few amps on the 12V rails, with most of the capacity on the 5V circuits, which doesn't sound like enough for a "500W" amplifier.

[badbradmx]

in all honesty im not sure, i dont think it does, but im sure it is possible to get ones that do. i think i mentioned im not too clued up on the amperage and stuff but it works perfectly fine, if it burns out i dont reli mind too much as it didnt cost me much. i just hope you found it useful

[stuuf]

Well, if your setup runs it must have enough power, at least for the volume level you're using. If you overload it by connecting low impedance speakers to all the channels and cranking up the volume, it shouldn't "burn out" anything; the PSU will just shut itself down when it hits the current limit.

[badbradmx]

oh that peice of information has really helped me, i was slightly worried id kill something. haha you wouldnt need it to go any louder that it does, trust me on that fact, il get a vid up tomorro maybe.

[frollard]

Also - as rated on the amp, it has a 25 ampere fuse, - so you need a line from the psu that can supply 12v at 25 amps. I'm not certain, but I think you can (and should) hook into multiple 12 volt lines to get enough parallel current. There's a reason that power cable is so beefy going into the amp, and so small coming out of the psu - it's just not meant for that much power.

[frollard]

Note: A 300 watt power supply, with all +12v rails tied in parallel, (http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply )
can only output 12 amps on the 12v rails...
one rail can only handle a LOT less.

[badbradmx]

ive checked out the ratings for my amp online and it says it draws a maximum of 21amperes, i think i mentioned using all the 12V rails in the 'ible. but i only showed using one as it was just easier, i am aware i need a more powerful supply :/

[frollard]

misleading picture :P caught me off guard. "us men don't read instructions, 2 or 3 pictures are good enough"

[badbradmx]

haha i agree there, but seriously any help on this matter is appreciated. i might add a information thingy on the pic for the men saying "use all 12Vrails" haha.