Power Supply A Guide to 12V PSU

Thehack

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Is there any advantage of choosing a long board version like below over a PDCB?



Also, for a general good practice, is it better to choose both the PDCB and the power brick of a same output wattage? Or is one supposed to be of higher wattage than the other for some safety reasons?

I would not choose a long board version because then you are concerned with mounting it. There is a small cost savings. Long board version is also easier to engineer higher specs or a wide input.

The output is only good up to the weakest spec link, so choose as your budget allows.
 
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BaK

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I would not choose a long board version because then you are concerned with mounting it. There is a small cost savings. Long board version is also easier to engineer higher specs or a wide input.
Mounting points could indeed be a problem, didn't think about that.

The output is only good up to the weakest spec link, so choose as your budget allows.
Weakest part is the limiting factor, got it.

Thanx once again!
 

Valantar

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In short, one does not just slap a capacitor and be done with it. At the very least you'd need an LPF (Low Pass Filter). Otherwise people can just slap a zener or two and be done with it, ha!
I'm well aware of how poor a "solution" (i.e. not a solution at all) adding a filter cap to the output is - best case scenario is a mild drop in ripple and noise (and worst case scenario is the capacitive load being too much for the PSU, causing it to oscillate and possibly frying anything connected to it). Definitely not something that will provide a clean output by any measure. I'm just testing it out as a cheap, compact and easy bodge to bring down slightly high ripple, for which it ought to do something. What, exactly, that something is is of course unknown, which is why I asked my brother to test this out on his oscilloscope. It's just too bad he hasn't got any suitable loads for proper testing, as what he had available at a moderate power draw was pretty much a pure resistive load which meant that ripple was very low even without anything added. Still saw a ~10% reduction FWIW. Still, I'm looking into other types of dummy loads.

Thanks for the video though, even if most of the stuff on that channel is far too advanced for me I still get the gist of it.
 

Curiosity

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Hello friends!
I've decided to drive my upcoming build with a 12v psu! Joining the club!.
A few questions though.

I'll be building an a300 stx based system, and so adapting the rear m.2 to pcie.
M.2 provides the 3.3v, and the aux floppy connector on the riser provides 5v and 12v.
Does the GPU need 5v? I was reading earlier about power flowing between power sources and if I could run all the 12v for the GPU off the 12v unit I chose, that would be optimal.
If it does absolutely need that 5v, do y'all reckon I could run a 5v line from the onboard sata connection of the Mobo and bring in 12v from my acdc unit?

The power plan right now (assuming my power draw test goes as I expect) is:

12v 200+W acdc power supply for the GPU 6/8 pin, maybe the floppy 12v connection?
+
Hdplex 80w acdc for powering the stx board, since it would mean I don't have to step up or down the voltage on its way to the mobo.

Thanks for any info you give in advance, and hopefully my post isn't confusing, aha!
 

Thehack

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You can run 5v from sata power and a separate 12V.

I forget but there's another thread of someone already done that. You will still need a way to control when 12v source is on or off.
 
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Curiosity

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I was thinking of wiring a switch to the ac inlet to interrupt power to both psus at once, so the shutdown sequence would be
Windows shutdown>ac inlet switch to off
 

Curiosity

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Weird but cool, not sure if it's just my 1060 cooperating or if this is normal, but my 1060 6gb is perfectly happy to run on the riser with the 5v line snipped.
 
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Curiosity

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Sweet.
I thought I read that there was so I was concerned, but even if there is it doesn't seem to matter, which is great.
 

Curiosity

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Double post, sorry.
 
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Curiosity

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Emailed Fidus power about their MWLP225 which is a 4"x2"x1" acdc unit.
Ripple looks good, I think? Assuming I'm reading this correctly.


Seems to be 100mv p-p

 

smitty2k1

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Emailed Fidus power about their MWLP225 which is a 4"x2"x1" acdc unit.
Ripple looks good, I think? Assuming I'm reading this correctly.


Seems to be 100mv p-p


Oh wow they also have 550w units in the 5"x3" form factor, and seem to be shorter than the Meanwell units - under 40mm height (no chassis though)
 

Curiosity

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That's why I posted here, I wasn't 100% sure how how to interpret it.
Worth noting that I was informed in their email with that graph, that they don't sell in the US, just the UK. which is pretty disappointing.

Sort of related, @confusis mentioned test running an Intel deskmini board on 12v instead of 19v before and it worked fine, so I'm currently testing my a300 on 12v from my g-unique archdaemon.
It's working great! P95+heaven ultra 8xAA 1600X900 windowed, no weirdness. (It is pretty hot though.:p)

 
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Thehack

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That's why I posted here, I wasn't 100% sure how how to interpret it.
Worth noting that I was informed in their email with that graph, that they don't sell in the US, just the UK. which is pretty disappointing.

Sort of related, @confusis mentioned test running an Intel deskmini board on 12v instead of 19v before and it worked fine, so I'm currently testing my a300 on 12v from my g-unique archdaemon.
It's working great! P95+heaven ultra 8xAA 1600X900 windowed, no weirdness. (It is pretty hot though.:p)


Thanks for taking the plunge. Gives me a couple ideas for an STX case.
 
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k0n

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I bought the EPP-400-12/picoPSU 160XT. It went better than expected.


Still the R9 nano but maybe I will get a RX 5700/XT in the future. Some of the material for my next case project arrived (350*260*55mm), but I really like the FX 4.7 and how the EPP-400 fits in there. Unfortunately no RX 5700/XT aside from the one on Amazon.jp.
 
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smitty2k1

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I bought the EPP-400-12/picoPSU 160XT. It went better than expected.


Still the R9 nano but maybe I will get a RX 5700/XT in the future. Some of the material for my next case project arrived (350*260*55mm), but I really like the FX 4.7 and how the EPP-400 fits in there. Unfortunately no RX 5700/XT aside from the one on Amazon.jp.
Do you have any more photos of how it fits in that CustomMod case? Any weirdness with the graphics card being plugged straight into the Meanwell without any additional circuitry? Did you solder the power connectors on to the Meanwell instead of using a plug? Looks great!
 

k0n

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I didn't make more photos yet. I will make some more when my C14 connector arrives.

No weirdness with the graphics card. The connections aren't soldered. On the AC side I used this type of crimp:


Which I widened a little bit and forced on the pin.