Seasonic Platinum SS-1050XP3 & SS-1200XP3 Power Supply Reviewby E. Fylladitakis on September 3, 2014 6:00 PM EST
Externally, both units are nearly identical, with the sole exception being the sticker with the specifications table on the left side of the chassis. The 190mm long chassis will most likely be too long for small cases, but these units are definitely not designed for compact systems. Seasonic's designs usually are subtle but the company has performed several modifications to enhance the aesthetic value of their top-tier units.
The circular fan guard has been replaced with a rectangular grey panel, with a honeycomb mesh pattern and a badge with the company logo on it. Seasonic added decorative engravings and printed the company and series logos on the right side of the chassis, where they will most likely be invisible, as they will be facing the right side panel of most cases. For these engravings to be visible from a windowed left side panel, the PSU will have to be installed with the fan facing upwards. If the fan is facing downwards, the decorations will also be upside down, so they are best left out of sight. On the left side of the chassis, the side that is visible from windowed side panels, Seasonic placed a sticker with the specifications of the PSU.
A typical C14 receptacle can be seen at the perforated rear side of the units, next to a large on/off switch. The front of the units is filled with connectors for the modular cables and there also is a switch that can change the fan's profile from normal to hybrid mode. The hybrid mode is a quieter thermal profile and allows the fan to be turned off entirely when it's not necessary. Finally, the company and series logos are printed here as well.
Seasonic went with a San Ace 9S1212H403 120mm fan in both of their newest models. It is a very powerful fan, with a top rated speed of 2700RPM. The specifications of the bearing/engine are not available from the manufacturer, but it looks like Sanyo uses a form of self-lubricating sleeve bearing. The life expectancy of this fan is 40,000 hours, a rather mediocre rating for similar devices, but it also translates to about 4.5 years of 24/7 use at 60°C, albeit this rating also is for a free, unobstructed air path (zero static pressure, max airflow).
Seasonic designs and builds their own units so there is no secondary / hidden OEM behind their Platinum series; these PSUs are entirely in-house productions. Both units share the exact same platform and design, with the obvious difference being only the ratings of both the passive and active components. For example, the 1050W version has three Nippon Chemi-Con 330μF capacitors at the PFC stage, whereas the 1200W version has three 390μF capacitors of the same type installed there. Aside from the component ratings however, the two versions do not have a discernible design difference.
The filtering components at the back of the AC receptacle are shielded in an effort to reduce EMI. The total number of filtering components is six Y capacitors, four X capacitors, and three filtering inductors, more than adequate for a strong filtering stage, even for units of this size. Moving towards the APFC stage, we can see the two bridge rectifiers on their own small heatsink, followed by a sizable APFC coil and three capacitors from Nippon Chemi-Con.
The active PFC components are on the long heatsink near the edge of the PCB, while the smaller heatsink towards the center of the unit holds the four transistors that form the full-bridge inversion stage. Two square heatsinks cool the active components of the secondary conversion stage, which are not directly attached to the heatsinks but are on the rear of the PCB. Nippon Chemi-Con supplies all of the secondary side capacitors as well, electrolytic and solid alike, making these units an all-Japanese affair.
When it comes to build quality, Seasonic has an excellent reputation for designing and building top-quality products; these two units however surprised us. Seasonic is definitely using top-tier components, some of the best that can be found in a consumer-grade product. The soldering job is excellent as well and we could not find a single bad joint or weak point. What confounded us however is that the assembly of the Platinum units is rather messy, which is a first for Seasonic.
It is not bad, not even average, but it does not live up to the standards Seasonic themselves have set. There are cables pressing against components and many electrolytic capacitors appear to have received mechanical force after they have been soldered on the board, tilting them left and right. Even the glue appears to have been spilt carelessly and purposelessly, as there are spots where it does not even touch the components it is supposed to. If this was true for just one sample, we could consider the possibility of it being an "isolated case", but both of the samples that we received share these flaws, so it is not random. Perhaps these are just pre-production or early samples, and we hope so, but we've seen better attention to detail in previous Seasonic units.