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- Date:
- Wednesday, January 14, 2009
- Author:
- Paul Johnson
- Editor:
- Kyle Bennett
- Google +1
Seasonic M12D-850 Power Supply
Seasonic is a common name to the computer hardware enthusiast that pays attention to his power supply. Seasonic in many ways has become the de facto standard when it comes to quiet PSUs. Today it states it is the new standard in silent computing. So what's new?
Build Quality
As we already know the Seasonic M12D-850 features a single 120mm fan design that has come to be the preferred standard for quiet cooling environments, which Seasonic has been the longtime leader in, due to the ability to move a larger volume of air at slower speeds than a smaller diameter fan. While great for quiet computing environments the key criteria in our evaluation is whether or not the cooling solution is sufficient, not necessary it’s sound level or form factor.
External Build Quality
Externally the Seasonic M12D-850 is trimmed in basic black with the same style finish that we have come to expect from Seasonic branded Corsair units. The only thing setting off the unit’s black exterior is the small blue Seasonic logo on the fan grill. The rear of the unit has the Seasonic logo once more and the on/off switch but no voltage selector switch as this unit is full range. The front of the unit houses the fixed connectors all exiting from one location and a small section running across one edge that has the modular connection points. Of issue here is the fact that these modular connectors are on different 12v rails and nowhere is this information provided for users in an easily accessible manner. However, once I opened the unit below I was able to trace which modular connector was fed by which rail and that information is provided back on page 2. Also, once completely disassembling the unit I found that the Modular PCB has the 12v rails labeled by each connector and users can get to this if they pry off the molding around the modular connector and look at the PCB through this gap.
The Seasonic M12D-850 comes in at a total length of ~6 1/4 inches while the cables all reach out to ~18 inches to the first or only connector. Now while the cables are all well sleeved in black mesh there is one issue here. Most multi-12v power supplies will have the 12v leads color coded on the insulation to identify which 12v rail is feeding which wire. This is almost the case with the Seasonic M12D-850, except for the fact that there are 5 color codes and two 12v rails. It looks almost as if all the left over wiring in the factory was just cobbled together for this unit and as such users should not rely on this method to determine which 12v rail is feeding which component.
Internal Build Quality
Once we open the Seasonic M12D-850 we are left looking at a power supply that shares the same general layout as the Seasonic x900 (branded in the US as the PC Power & Cooling Silencer 750) as the primary capacitor and main transformer are situated in the center of the unit. The heatsinks here are fingered and bent to better match the overhead fan design that this unit employs and the fan charged with cooling this unit is a Sanyo Denki rated at 0.39A at 12v. From the top the build quality of this unit looks good.
On the primary side we see two heat sinks with the smaller one hiding the APFC coil and some of the input filtering. The remaining power components are on the large heatsink while the transformer is in the center of the unit with the main filtering capacitors. These main filtering capacitors differ from the x900 and x900 based units in that they are a pair of Nippon Chemi-con rated at 400v 390uF 105c as opposed to a single capacitor.
Over on the secondary side we see part of the input filtering housed by the AC receptacle while the DC-DC VRM is tucked in behind the wiring. The secondary capacitors are all once more Nippon Chemi-con for the normal capacitors which is certainly good. The solid capacitors on the DC-DC VRM are provided by United Chemi-con which is also a very good selection. Towards the front of the unit we see the fan controller connection right where the wiring splits to go to the fixed connectors or to the modular interface. The wiring itself is sleeved all the way back into the housing for the fixed wires and well bundled/routed for the wires going to the modular interface. The modular interface itself is well constructed and has an acetate shield behind it. As was mentioned earlier, the 12v rail breakdown of the modular connector is printed on the front side of this PCB and is visible when the trim around the modular connectors is removed.
Build Quality Summary
The overall build quality of the Seasonic M12D-850 is very good as we have come to expect from high-end Seasonic products. The only annoying part is the miscoded wiring, but the majority of users will never even know that it is miscoded. The exterior of the unit is trimmed out in typical Seasonic subdued black but with a high quality fit and finish. The cables are well sleeved which is also very nice to see. Once we move to the interior of the unit we find the build quality continues to be excellent. There is no real cost cutting in the component selection as is evidenced by the all Nippon Chemi-con capacitors for the standard electrolytics and United Chemi-con for the solid capacitors. The unit also has a very neat over all construction that is good and we can see all the components well seated with all the solder work being neat and tidy including on the modular interface. As we stated a moment ago this is all very good, so let’s see how this unit performs!