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Car Subs in your room?


AndonD454
11-18-2004, 09:21 PM
Hey just from checkin out some of the posts i noticed some of you guys have car subs and amps connected in your rooms at home... i have heard of people doin this but have never seen it.. i know i would love to throw a 12 in my room cause home audio subs usually seem to suck for the 300 or more that you pay for em.. anyways.. how would you run a car amp in your room? and also, does this run your power bill way up or is it not too bad?

sr20de4evr
11-18-2004, 10:31 PM
I use an old computer power supply to run the car amp, works well but it can only handle ~80rms (depending on the amp's efficiency).

If you don't have a car amp that you can use, you can buy a decently powerful plate amp for pretty cheap from www.partsexpress.com

Mannyb18b
11-19-2004, 11:32 AM
Actually i would like to no this also, I have an extra amp and sub. Now this computer supply? what exacly is that?where can i find one? and are there any other choices?

hightek
11-19-2004, 02:48 PM
one thing you can do is buy a power inverter from like Radio Shack or something that converts 140 volts to 12 volts or whatever. then hook you amp and stuff up

one thing i did was just hook up the subs and some speakers i ripped out of my sister's car to a home stereo reciever in my house and turned it up. it hit hard enough that a picture fell off the wall.
here's a link if you want to see it.
http://groups.msn.com/allabouttekNOLOGY/shoebox.msnw?action=ShowPhoto&PhotoID=27

Mannyb18b
11-19-2004, 02:58 PM
I have a home stereo reciever, what did u hook up the power cable too? an remote wire?

sr20de4evr
11-19-2004, 04:46 PM
I have a home stereo reciever, what did u hook up the power cable too? an remote wire?

don't try that, it's a very very bad idea and you're just asking to permanently damage the receiver

sr20de4evr
11-19-2004, 04:51 PM
Actually i would like to no this also, I have an extra amp and sub. Now this computer supply? what exacly is that?where can i find one? and are there any other choices?

You know the thing on the back of your computer with the I/O switch and the plug? That's the power supply, it has a 12V output that runs your hard drive, cdrom, etc. This 12V output can handle a 10-20 amp draw depending on the model, which is enough to give your sub(s) anywhere from 70-200 watts, depending on the power supply and the amp's efficiency. A power supply that can handle a 20amp draw is going to be close to $100, which is about the same price as a power inverter of the same size. The power inverter would be a better choice, but the PSU (power supply unit, aka computer power supply) is a good option if you have an old computer sitting around that you aren't using.

Then agian, a power inverter isn't a very good choice either unless you plan on using it to bench test various amps, because you can get a real home sub amplifier that will supply 1-200 watts for about the same price.

Mannyb18b
11-19-2004, 05:18 PM
Well i dont have any extra computers lying around so i dont think the PSU is going to work. So i guess the power inverter is going to be my choice, about how much do they cost?

sr20de4evr
11-19-2004, 05:33 PM
around a hundred, about the same price as getting a plate amp, and if you get a plate amp you don't have to worry about the inefficiency of a car amp dropping your output power, or looking ghetto by having a car amp sitting in your room.

CBFryman
11-19-2004, 09:03 PM
sr20 where do yo uget your power supplys from. i have a 300w on 12(+) (25amp peak, 15a RMS). it cost me $15. of corse my dad owns a computer business (CSR, Computer Support Resources inc.) and that was the stock price. he charges $35 for a replacement plus labor. i havent really looked around. but i am fixing to buy another of the exact same one to wire in paralell with one i have now to give me 50amp peak and 30amp RMS. then im going to buy a tempest. as my audiobahns are up for sale.

most old computers that have ATS power supplies are 4.2amp peak. thats about 50w peak... so no an old power supply isnt going to work.

as for how to use it. well you will nead to short out the 3v (+) and 1v turn on lead inside the supply its self to make it turn on when you flip the switch.

as far as the Rem turn on. just take one of the 12v (+) leads that comes from the power supply (should be at least 5) to your REM input. simple as Pi^2*(6.24*10^23). just watch out when working on shorting hte supply internally. there are three 0.25 farad 240v capasitors what will shock the balls out of your nut sack if they are charged up and your hand goes across the leads.

most all audio equiptment has at least RCA. which is universal. so there is no problem getting the soud to the amplifier.

the thing i like about using car amplifiers is that alot of htem are 1ohm stable where as most home audio stuff is never less than 4ohm stable.

problems? none really. wiht my bahns i was getting about 40% of the maximum displacement with the 200RMS and 300peak it was supplying. there is that ever present 60Hz buzz that is caused from the power supply never being able to completely change 120v 60Hz ac to DC current. a noise gate will fix that. and if your gains are set too high and you really start pumping the bass the internal thermal circut breaker will switch off. you can fix this by switing it out wiht one allowing more amps. but that may cause a fire hazard so i wouldnt reccomend it.

because of all of the electrical work needed to get the power supply Home stereo worthy i reccomend a 12v supply ment for test benches. it will be far more expensive (a 40amp one cost over $200) but will supply a more constant power source and it wont cause that constant buzz.

the only other thing i could really think of using to ghetto rig it is a bass head off of a bass guitar amp. but they cost even more than most power supplys and car amplifiers for good hihg powered ones.

sr20de4evr
11-19-2004, 09:46 PM
I get mine from www.zipzoomfly.com
and that 60hz buzz will only come if you have a shitty PSU that, like you said, is incapable of creating a true DC output like it should. I've never gotten that, but then again I don't use $30 PSUs either.

And you're right, most plate amps can't run below 4ohm, but how many subs do you know of that can't be run at either 4ohm or 8ohm?

CBFryman
11-20-2004, 08:39 AM
well thats true. well the weird thing is, there is no 60Hz buzz when there is no input signal from the JBL unit. but then i looked at teh RCA output with a friends ociliscope (i love my connections, hehe) and the 60Hz wasnt coming from the RCA's so it had to be the power supply...either that or the crappy amp i am using...

i dont know why someone would put a $100 supply in their computer when hard drives, CD drives, etc.. are not efected by a an extra, very small, distorted signal.

oh well. as soon as my audiobahns sell im getting:

Tempest
Another Computer Power Supply 25a peak.
5.1 digital reciever
dolby digital surround amplifier for use with an active subwoofer.

then ill run it in stereo untill i get the money to make 2 satalite speakers and a good center chanel.

i really think music should start to be recourded in at least Dolby 4.1 i mean its so easy to get 4.1 in vehicles. most cars already have 4 speakers. it would be nice if it was recorded in dolby 7.2.... and then automanufactures would start to get their cars THX certified...lol

sr20de4evr
11-20-2004, 01:52 PM
i dont know why someone would put a $100 supply in their computer when hard drives, CD drives, etc.. are not efected by a an extra, very small, distorted signal.


Power and reliability, the PSU is normally one of the first things to go in a computer. When I build a $2000 computer, I don't cheap out on the PSU just so it can die on me within 2 years.

Also, the method of getting them to turn on without a MB attached depends on the PSU, on ATX PSUs the remote is an active low, so you have to short it to ground for it to turn on.

CBFryman
11-20-2004, 03:42 PM
2 years? the power supply that came in the case on this computer is in went out after 1.5years. i replaced it with a $40 one Computer Warehouse, Orlando, FL (one of my dads business's supplyers) and that was 3 years ago and its still going strong.

sr20de4evr
11-20-2004, 04:52 PM
I'm not saying they all go out after 2 years, just that they don't last all that long usually

GSteg
11-20-2004, 08:53 PM
personally, i would use the plate amp. The power supply will work, but they will be stressed out when the amp demands a surge of power.

not to mention, PE will sell u the plate amp with a cool remote control. :p

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