Corsair AX860 Modular Power Supply Review

A look inside the AX860

Unlike the vast majority of Corsair’s units which are being cooled by Yate Loon fans, the cooling fan of the AX860 is provided by Sanyo Denki. It is a fairly fast 120mm fan, capable of reaching a maximum speed of 2200RPM. With dual ball bearings, it may be not the quietest fan around but it certainly is one of the most reliable.

Here is where the major difference of the AX860 in comparison to the AX760i/AX860i models lies; this is no Flextronics design at all, as Corsair chose their old friends at Seasonic to be the manufacturers of this power supply. This makes the AX860 virtually nothing more than an upgrade of the older AX850, as Corsair switched from the second generation to the third generation KM platform. Seasonic is relentless when it comes to the quality of their high-end designs and the AX860 is no exception; both the soldering job and the assembly quality are nothing short of textbook.

Seasonic placed a small PCB at the rear of the A/C receptacle which holds some of the input filter components and shielded it within a metallic cage to prevent EMI interference. The total filtering stage components are six Y capacitors, three X capacitors, three chokes and a MOV, many more than the minimum required to build an effective transient filter.

Moving towards the APFC, we found the two bridge rectifiers mounted on their own small dedicated heatsink, right before the sizable coil. Two Nippon Chemi-Con 400V/390uF 105°C capacitors complete the primary filtering stage passive components. The active components, two transistors and a diode, are on the large heatsink at the edge of the main PCB. The smaller heatsink towards the main transformer holds the four inversion transistors, which form a full bridge topology.

An LLC type rectifier is being formed on the secondary side of the AX860, housed on the short vertical PCB next to the main transformer. The peculiar looking heatsink is used to cool the rectifier’s transistors. Around the secondary side we found Nippon Chemi-Con electrolytic and Enesol solid state capacitors.

Seasonic moved the DC to DC converters which generate the 5V and 3.3V lines directly on the PCB which is holding the modular cable connectors. Additional filtering takes place on this PCB as well.