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240v To 12v


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hey.

i want to put a car stereo and sub and amp in my garage, but i wanted to know the safest way to do this without risk of burning it down.

your probably going to say, why would you want to. but i have a a few subs and amps laying about and a car stereo so i thought i would make use.

also i think you can achieve more bass and more tuneability at a lower cost with incar audio.

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I remember my teacher in high school years ago had a car stereo setup in one of the technology rooms but I never got round to asking him how it was all done but then again at that age I didnt know much about cars lol. I've always wanted to know how to do this tho. Would make an interesting sound system.

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cool.

i did have a look on ebay and see a similar item. but i was a bit unsure if that kind of thing was up to the job. i was thinking of running a couple of alpine v12 amps and a couple of subs. thats going to take alot of power and i think they run at 14.4v. is that a problem?

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Stav you can't be serious surely ? :o :unsure: :o 12v 1 amp ? :lol: :lol:

If running a car amp, and driving a sub (or subs with it) you will need a regulated 12v with an output

20-30amps (all depending on what the amp actually needs). 12v power supplies are quite expensive

with that kind of output I think.

An alternative would be (just to fire things up) an old car Battery. It would need charging often tho mate .

I know of a guy who ran a CB Radio (back in the 80's) from a car Battery connected to a Battery charger

all the time. He said it was fine...... I wouldn't suggest this tho :o

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An alternative would be (just to fire things up) an old car battery. It would need charging often tho mate .

I know of a guy who ran a CB Radio (back in the 80's) from a car battery connected to a battery charger

all the time. He said it was fine...... I wouldn't suggest this tho :o

Ah, CB radio, the 80's equivalent of mobile phones/MSN Messenger :D

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Something like this might do the trick:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...5032d63ffeada75

The problem you'll have with things like subs is that they will pull big high-current transients off the power supply - so you'll need a significantly bigger supply so meet those transients than would be required at other times. This is particularly a problem with switching (as opposed to linear) power supplies.

Linear supplies are large, heavy and expensive, however.

Another option would be to use a PC ATX power supply - they are mass produced, quite cheap and safe. You would have to connect ground and 'Power On' (pins 14 and 15) together with a resistor to get the PSU to come on.

The pinout for an ATX supply looks like this:

http://wiki.xtronics.com/index.php/ATX_Pinout

Most PC motherboards pull a lot of current of the 12A line and convert it internally - therefore, the PSUs can provide a lot of current at 12v. You might need to common several of the 12V outputs together... you'll need to read the PSU specification and know what you're doing to do this.

An example is this thing, which chucks out 72A worth of 12v (apparently... not quite sure how that makes it qualify as an 800W power supply):

http://www.quietpc.com/gb-en-gbp/products/...601-1000/x-800w

One last thing - make sure you use a suitable 12v fuse as you will get smoke pretty quickly if you short something out with that sort of current.

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kelraine - uve lost me already!! lol i kind of understand what u mean but im very confused. i wouldnt have a clue how to wire it up.

is there a dummy option where i can just plug it in? or would you be able to walk me thru it if you tell me what i need to buy?

yeah i used to mess around on the cb radios when i was a kid. great fun!!

but without googling it - do u know what cb stands for? i would never of guessed until someone told me years ago.

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Difficult to talk you through it and wouldn't be too happy incase it caught fire or 'owt.

How big is your system going to be? If you're talking a couple fo hundred watts, then you'll probably need at least a 20A power supply.

Maplin do something that would just plug in - it costs about £100:

http://www.maplin.co.uk/Module.aspx?ModuleNo=30391

You can set the voltage manually, and it'll give between 25 and 30 Amps (so, between 300 and 360 Watts). It mentions that it has a cooling fan, which might be annoying.

An alternative, like I mentioned before, is to use an 'ATX' power supply of the type that's used in a PC. These typically have a connector that goes onto the motherboard with lots of voltages on it, and then a few 'hard drive' Molex connectors that have 12V and 5V on them - so, if you got one of these then you would be able to get 12V off the Molex connectors - and the amount of current you can pull off each connector depends on the design of the power supply. You really need to know what you're doing if you do this.

This website shows the various connectors that come off a modern PC power supply:

http://www.smpspowersupply.com/connectors-pinouts.html

The two things you are interested in are the 'Main Power Connector' and the 'Peripheral Connector'

To make the power supply turn on, you need to connect the 'PS_ON' pin on the main power connector to a ground pin (marked as 'COM'). When it is powered on, you'll get 12v coming out of the peripheral connectors on the pins shown. To get more current, you'll need to connect your stereo gear to more than one of the 12V connectors.

If you have any doubts at all about how to do this then I'd suggest you just got for the Maplin power supply, as it just has two connections on it.

Hope that helps...

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yeah citizen band!! ;)

that mapling box of tricks looks like the thing im looking for. im looking to put probably 2 amps on it. one for the speakers and one for the sub.

there probably going to be the alpine v12 amps as i have a couple spare.

what would happen if i over power it? would it break it or just cut out?

i think ive got a 30a fuse on the stereo as it is in the car now, so it would be fine to run them on this wouldnt it?

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If you bought the Maplin kit, it (probably) has current limiting - so it'll just cut out until you reset it.

You'll probably get 25A at 14.4 - which gives you 360W - I'd guess you'll have seriously annoyed your neighbours before you get anywhere near that level of power in a garage, so should be okay. If you want to connect two amplifiers to it, just connect them in parallel.

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Difficult to talk you through it and wouldn't be too happy incase it caught fire or 'owt.

How big is your system going to be? If you're talking a couple fo hundred watts, then you'll probably need at least a 20A power supply.

Maplin do something that would just plug in - it costs about £100:

http://www.maplin.co.uk/Module.aspx?ModuleNo=30391

You can set the voltage manually, and it'll give between 25 and 30 Amps (so, between 300 and 360 Watts). It mentions that it has a cooling fan, which might be annoying.

I hopefully getting one of them for christmas, sad i know but so useful for little projects. dont have to keep going back to the car to check it.

Stav

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hey.

i want to put a car stereo and sub and amp in my garage, but i wanted to know the safest way to do this without risk of burning it down.

your probably going to say, why would you want to. but i have a a few subs and amps laying about and a car stereo so i thought i would make use.

also i think you can achieve more bass and more tuneability at a lower cost with incar audio.

I can do you a 30AMP or 50 AMP or 80A or even a monster 250A one, email me csdesignsteve@aol.com

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Halfords radio displays used to use 13.8V CB power supplies, either 5 or 7 amp. SparesWorld used to use something a bit bigger for their sub displays, a Manson EP 850. This thing's the same size as a hi-fi amp, weighs a ton and kicks out 13.8V at 50 amps. I've got one that I've fitted a cigarette lighter socket to. Here's a stock photo of the beastie, though.

p_EP850.jpg

On the other hand, a Corsair TX 650 can kick out 52A on its 12v rail, you just need to modify it a bit.

http://www.wikihow.com/Convert-a-Computer-...ab-Power-Supply

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