As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.

Even though this power supply has one X capacitor and two Y capacitors more than the minimum required plus one extra coil and one extra X capacitor after the rectification bridge, it doesn’t come with a MOV, which is the component in charge of removing spikes coming from the power grid. This stage from the 400 W model is superior, as it features a MOV.

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Figure 7: Transient filtering stage (part 1).

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Figure 8: Transient filtering stage (part 2).

In the next page we will have a more detailed discussion of the components used in the OCZ StealthXStream 500 W.