Power Supply The Seasonic SSP-300SUG fully modular 150mm FlexATX PSU

Hahutzy

Airflow Optimizer
Sep 9, 2015
252
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IMO the best solution, disregarding MOQ and money needed, is this:

SeaSonic's pinout assignment is actually not the best. By rearranging the pinout, you can get that single 24pin connector to split into 3 modular harnesses:

1. EPS (4 pins)
2. 24-pin motherboard (14 pins)
3. PCIE 6+2 and/or SATA (6 pins)

They would stack onto each other like those 20+4 pin connectors, with ledges that link to each other for support.



Like this picture above, but imagine the left side is also a separate piece that's 6 pins. And the middle is 14 pins.

These harnesses will have custom pin mapping (see below), so they won't be transferable elsewhere like the HDPLEX's.

But they jam "44 pins" worth of connectors onto that 24 pin connector.

Assumption: Each pin on the harnesses can only fit 2 wires coming out. Theoretically you can stuff 48 pins worth of wires in there.

Caveat: SATA connector will NOT have the 3.3V pin. This was a choice made because otherwise 25 pins are needed. 3.3V is never really used by any SSD because manufacturers design around the fact that people use MOLEX -> SATA adapters.

 
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iFreilicht

FlexATX Authority
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Feb 28, 2015
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As you can see by the photos below, you'd essentially be looking at about 17cm long and no change in overall height. By coincidence this is exactly the length of an ITX motherboard which is as far as I'm concerned perfect.

Aha you see that's exactly what I feared, it needs 20mm of additional space above the PSU to work, so in my book it increases the height.

IMO the best solution, disregarding MOQ and money needed, is this:

SeaSonic's pinout assignment is actually not the best. By rearranging the pinout, you can get that single 24pin connector to split into 3 modular harnesses:

1. EPS (4 pins)
2. 24-pin motherboard (14 pins)
3. PCIE 6+2 and/or SATA (6 pins)

They would stack onto each other like those 20+4 pin connectors, with ledges that link to each other for support.



Like this picture above, but imagine the left side is also a separate piece that's 6 pins. And the middle is 14 pins.

These harnesses will have custom pin mapping (see below), so they won't be transferable elsewhere like the HDPLEX's.

But they jam "44 pins" worth of connectors onto that 24 pin connector.

Assumption: Each pin on the harnesses can only fit 2 wires coming out. Theoretically you can stuff 48 pins worth of wires in there.

Caveat: SATA connector will NOT have the 3.3V pin. This was a choice made because otherwise 25 pins are needed. 3.3V is never really used by any SSD because manufacturers design around the fact that people use MOLEX -> SATA adapters.


That's a much neater idea, but while you're at it, why not just make them three separate connectors instead of interlocking ones? You only need about 5mm more width, which certainly seems available.

You could even implement this rearrangement with something similar to what @ilovelampshade was proposing, but taller with the sockets on the same side as the connector that plugs into the PSU. That way you might even be able to get four separate harnesses instead of three if you do it cleverly.
 

Hahutzy

Airflow Optimizer
Sep 9, 2015
252
187
The thought was that SeaSonic would be able to OEM that without sourcing new connectors for the unit itself.

If they are going to source new connectors though, separate connectors is most likely possible.



(Pin keys are change to match the common key pattern of 6-pin, 14-pin and 4-pin connectors respectively)
 

iFreilicht

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Feb 28, 2015
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The thought was that SeaSonic would be able to OEM that without sourcing new connectors for the unit itself.

If they are going to source new connectors though, separate connectors is most likely possible.



(Pin keys are change to match the common key pattern of 6-pin, 14-pin and 4-pin connectors respectively)

That's a very good setup! You can even plug a 4-pin connector into the 6-pin and it will work without a problem. That looks like a good solution!
 
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iFreilicht

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So, I just got a mail back from my Seasonic rep. Not that I'm really considering this unit anymore, but this might be useful information.

Firstly, he couldn't give me any information about the part number of the modular connector. So if you want to make a different cable harness, you'll either have to live with the fact that you can't use the locking tabs or you'll have to repin the stock connector.

Secondly, he said that their unit is actually not out of spec and that it was approved and certified the way it is after the intel specs. Maybe the reference values we know for FlexATX PSUs were updated in the past?
 

Hahutzy

Airflow Optimizer
Sep 9, 2015
252
187
Ok in a surprising turn of events, Seasonic actually got back to me with an updated drawing saying they will move the C14 connector down 1mm. Must be because I kept badgering them with "look, the screwhead doesn't even fit here".

I have not proposed the pin changes yet. I don't want them to label me as a crazy by going hard on all the changes at once.

Let's see where it goes from here.
 

iFreilicht

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Feb 28, 2015
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Nice, those are good news. Any idea when those "Rev1.1" units will hit the market? Because obviously, if you sell a case for FlexATX you'll have to issue a warning that rev1.0 won't fit.
 

Hahutzy

Airflow Optimizer
Sep 9, 2015
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They acknowledge that they will lower the connector by 1mm, but they did not give an ETA yet.

I also asked them to use a smaller C14 connector because it is thicker than the FSP one. On that point, they said that "to change the AC inlet would require recertification", so I did not push further on that ground.

I told them to let me know when the revised version is ready for sale.
 
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lordzahl

Trash Compacter
Feb 7, 2016
54
10
I also have this PSU, and while it is not loud at idle, it is still very noticeable. Thanks Freilicht for all your pictures! I am thinking about replacing the fan, but i don't want to risk a fire hazard. This fan is specified for more than 20m^3/h and most other i found, are specified for a maximum of about 12m^3/h.
Should this be a problem? Or can i mod the original fan, so it runs slower? The maximum rpms are probably the difference between the m^3/h
 

iFreilicht

FlexATX Authority
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Feb 28, 2015
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but i don't want to risk a fire hazard

Don't take my word for it (I don't want to be held responsible if your house did indeed burn down), but I don't think your PSU can burst into flames because of that. It will do an emergency shutdown much before that.

And the lowered airflow on other fans will absolutely be a problem under load, the PSU will not be able to output 300W continuously. Under idle, it might not matter.

I've posted one picture of the fans label, so you can try to find out what kind of motor it uses and search for a fitting method to reduce RPM. In any case, a variable resistor in series with the positive input of the fan should be worth a try.

Alternatively, you can use the model number to find other fans by that manufacturer of that series with a lower maximum RPM, that might be a relatively safe way to reduce the maximum power and idle noise of the PSU.
 

mantide

Trash Compacter
Sep 17, 2016
42
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As you can see by the photos below, you'd essentially be looking at about 17cm long and no change in overall height. By coincidence this is exactly the length of an ITX motherboard which is as far as I'm concerned perfect.


Man that adapter is so cool! I registered this forum so that I could ask you, where did you get it?
 

lordzahl

Trash Compacter
Feb 7, 2016
54
10
Hey, I have to bring back this thread.
As you know, i also own this PSU and i also got recently my hands on a Rx470 8GB (Asus Strix).
Unfortunately, i also experience spontaneous reboots, probably because of a power problem.
The rest of my system is a Z170 mITX Mainboard, I5-6500, 1x8GB Ram, 2.5" SSD + 2.5" HDD.
I measured the power power input before the PSU with a cheap plug, and it was always below 200W. GPU-Z reported a maximum of ~143W power delivery to the GPU shortly before the reboot. But most of the time, it is much lower 100~120W.
The GPU is connected using a 1x PciE 3.0 Riser atm. I also have a cheap 16x Riser, but this one showed also reboots. My old GTX 750 Ti worked flawlessly in this system using the 1x Riser. Of course that was a slot only powered 75W TDP card.

Does anybody has some comments? The reboot seems like a power problem, but from my measurements i am far from the PSU power limit.
Otherwise has someone any recommendations for my power needs in a flex-atx or smaller package (SFX does not fit my case, and quiet would be very welcome)? A DC-DC solution might be okay, but since this is a (more or less) cheap system, i don't want to spend too much money, and the DC-DC solution in this power range tend to get expensive.
 

Ceros_X

King of Cable Management
Mar 8, 2016
748
660
Do you have an ATX psu you could borrow to test the system with - operating outside the case, of course?
 

lordzahl

Trash Compacter
Feb 7, 2016
54
10
Do you have an ATX psu you could borrow to test the system with - operating outside the case, of course?

Yeah also thought about that.
Hm i have one laying around, but i think it is not ok. But i will ask a friend.
I do have another (220W) Flex Atx PSU. Could use this only for the GPU (for testing), so two PSUs, one for Mainboard/CPU, one for GPU?
 

lordzahl

Trash Compacter
Feb 7, 2016
54
10
I replaced the SSP-300SUG and indeed it seems to be faulty. I now used the ENP-2322C, a 220W (16A on 12V) Flex-ATX unit. While it gets warm (and kind of noisy) it does not produce a reboot.
I checked again with the SSP-300SUG: It does get only very slightly warm on the underside. Still after a couple minutes of gaming, it reboots my PC.
So i am pretty sure it is well below its power limit and also not overheating (or only a very small part of it is overheating, which does not change the temperature of the casing at all?).
At the moment i get power for the GPU via a Molex->6Pin Adapter (which is ok with the ENP-2322C). Maybe i should try using two pairs of cable to supply the GPU? But since the PSU has only one rail, that would not make a difference?
Thanks!
 

iFreilicht

FlexATX Authority
Original poster
Feb 28, 2015
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You are correct, with the PSU only having one rail, there shouldn't be an issue. Is the PSU getting progressively louder as you play? Did you make a custom harness for it? If the latter isn't true and you're only using adaptors, ask Seasonic or your seller for a replacement and describe the exact behaviour you witness to them.