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Can i combine the 12v rail on multiple power supplies?

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  • Power Supplies
  • Components
Last response: in Components
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July 22, 2011 3:14:48 AM

ok well, not sure if any of you guys remember my thread before about combining 12v rails n stuff etc. but anyways, instead of buying a new power supply, i got a few old ones lying around here...now i was told as long as you know which rails are for what, PSU's with multiple rails CAN be combined, but can you do that with the 12v rail of 2 different supplies? or will it just fry both? the reason i ask, is because i dont own a vehicle so all my stuff is in my room, my amp is 560w, my current PSU powering it can only deliver 19A on the 12v rail (bout 228w) so, is it possible for me to also wire in my other psu that has 15A, so they would combine and deliver 34A (im assuming it'll be a little bit lower because of resistance) to the amp?

the only reason im making sure first instead of just going for it, is because they are the only 2 power supplies i have left, and if they blow, i dont got a car battery atm to put in my room for my subs, which = screwed till i get a new psu =\

anyways please respond =) and thanks for ur help, sorry for the unorganized and kind of out-of-the ordinary question =P

More about : combine 12v rail multiple power supplies

a b ) Power supply
July 22, 2011 8:08:41 AM

if you not professional electrnic .. it's very dangerous !
You Will Need:
1) A psu, or two if you want dual PSU's!
2) Screwdriver. Phillips head.
3) Electrical tape or heat shrink.
4) soldering iron (not really needed but you can use in for this mod. i'll sya were but to be honest i didn't use one this time)
5) Wire cutters.
6) A paper clip.

http://www.burningissues.net/how_to/power/complete.htm
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a c 94 ) Power supply
July 22, 2011 8:52:08 AM

Car audio in your room?

If you have a 500W+ amp, 34A on a 12V rail won't cut it. It can only output 408W. You'll pull to much from the PSUs, and they should eventually (or quickly) burn out.
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July 22, 2011 2:29:11 PM

@henydiah thanks! seems like alotta work o.o but then again if i can get better sound quality from bein able to supply (mostly) full power, i guess its worth it lol



@4745454b well, the amp can only take what the psu's can put out, i've been running the amp with my psu that only gives 19A for the past few months now, im only expecting it to last until october when i can buy a car =P
and i figure 34A either way would be better then only havin 19A especially when the 2 10" subs i ordered arrive, i dont expect them to sound great along with my 12" sub with only 19A (228w) power lol
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Best solution

a b ) Power supply
July 22, 2011 3:06:23 PM

DO NOT put Two powersupply outputs in Parallel.

You can put two batteries (Same voltage, different A/Hr ratings) in parallel. Ie a 1.5 V C cell in parellel with a D Cell. Batteries internal resistance will equalize out.

You can not do this with power suppys as one will become a "source" and one a "load " They will have a different internal resistantance that will NOT equalize and unless you can adjust the two outputs to exactly the same voltage you have a good chance of blowing one. It all depends on Internal resistance and the differential between the two supplies.

You can use two PSUs to power a system, As long as the outputs supply power to two differnent circuits and the Two (+) lines are NOT shorted together - OK for the Rtn lines to be shorted.
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July 22, 2011 3:43:25 PM

hey, i remember you helping me with my old question about rails =P so basicly the ONLY way to do that is if its combining rails from the same unit? otherwise the current just travels to the other unit?

with that being said, would it just be easier to invest in either a single rail psu, or a multi rail psu and combine the rails instead of possibly blowing something/zapping myself?
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a b ) Power supply
July 22, 2011 3:54:08 PM

Recommend single, single rail PSU.
I do not even recommend putting 2 +12V rails on a multirail PSU in parallel. They have a inline current limiting circuit which could cause a problem.
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July 22, 2011 4:11:53 PM

kk, well looks like i know what im saving for next lol, would i recommend i get a capacitor first? or a psu w/ a higher 12v rail first? or does it really matter? lol cuz i was told capacitors after the coil inside them heats up, they can also help deliver more power if your psu is running @ its limit (also i think why people use them to stop their headlights from dimming out)
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a c 144 ) Power supply
July 22, 2011 4:25:09 PM

That is not what the capacitors are for. An audio amp presents a highly variable load to the power supply. The capacitor serves as an energy storage device. During high peak loads, it can temporarily provide more current. If your power supply is running flat out, a cap will not help.
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July 22, 2011 4:47:44 PM

so, get the power supply first...lol gotcha, mmkay i think i've gotten enough info to be happy for now =D thanks guys for all your answers, hope to see you around again with any other questions i have about power supplies and other computer questions, =) so far this has been the most helpful forum i've joined
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July 22, 2011 5:03:39 PM

Best answer selected by kryptonite666.
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a b ) Power supply
July 22, 2011 5:59:53 PM

This topic has been closed by Mousemonkey
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