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Author Topic: Can I run a car stereo off of a 12 volt power supply without a battery?  (Read 10243 times)

Offline 73A37

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I'm creating a home stereo/boombox that will have a head unit powering four  6 1/2 " speakers and a 350 watt amp powering a couple subs. The power supply is 55 amps and I am worried that that will be too much for a 10 amp head unit. Will the power supply blow the head unit, or do the head unit and amp just draw from the power supply what they need?


 

Offline alancalverd

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No problem.
 

Offline evan_au

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350 Watts divided by 12Volts = 29 Amps.

Most electronic amplifiers have efficiency that is much better than 50%, so I am a bit surpised at the 55 Amps described. (Is it a valve amplifier, or perhaps 350W per channel? Or is it an electronic amplifier tryig to act like a valve amplifier; these "Class A" amplifiers are very inefficient.)

Provided it is not a "Class A" amplifier, the amplifier will only draw the power that it needs. It will only draw the maximum current if you are playing a sine wave on maximum volume (like an incredibly loud flute). Most of the time it will draw far less power.

Fuses take a little while to blow, so provided the average current is less than 10 Amps, the fuse will be fine. An average current of 5 Amps with peaks to 30 Amps is a believable combination.
 

Offline 73A37

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This is the power supply I settled on. newbielink:http://www.trcelectronics.com/View/Mean-Well/SE-600-12.shtml [nonactive]
I wire up car stereos all the time but it's slightly unfamiliar territory converting ac to dc and I want to make sure I do this right so it lasts a long time.
I have been building little boxes for truck drivers using a 40 Dollar head unit/speaker kit, and was amazed at how I could make it sound in a box that was built properly for the acoustics.
So of course I decided to go "balls to the wall" and make a solid jam box that you can't buy in stores. Well, at least not for 300 bucks or less.
If anyone has any suggestions feel free to pipe in, this is my first project like this, and pictures will be coming up shortly.
 

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