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, yellow component on the pictures below) and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.

This power supply is flawless on this stage. Its AC connector isn’t a regular plug but in fact a full line filter (we’ve seen similar component being used on another power supply manufactured by Impervio, OCZ EliteXStream 1000 W). It also has two more ferrite coils and one more X capacitor than necessary, plus one X capacitor and two Y capacitors after the rectifying bridge. The MOV is located after the rectifying bridge.

click to enlarge
Figure 8: Transient filtering stage.

In the next page we will have a more detailed discussion of the components used in the Decathlon 700 W.