The first place we like to take a look when opening a power supply to have a hint about its quality is its filtering stage. On generic power supplies this stage has only one coil, two ceramic capacitors, one or two metalized polyester capacitors and, if we are lucky, one MOV (Metal-Oxide Varistor). This power supply from Antec uses one MOV (behind the ferrite coil on the right in Figure 9, so it couldn’t be shown), two ceramic capacitors, two metalized polyester capacitor, three ferrite coils, plus a ferrite bead on the main power cord.

Also, the components from the first stage of the transient filter are usually soldered on the main power connector, but on this power supply they are located on a small printed circuit board attached to the main power connector, which is far better than having components directly soldered to the main power connector.

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Figure 8: Transient filtering stage (part 1).

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Figure 9: Transient filtering stage (part 2).

In Figure 9 you also see a ferrite coil, a ceramic capacitor and a polyester capacitor that are used on the active PFC circuit.