As we mentioned on other articles and reviews, 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. The recommend 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 than that, 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.

Now let’s have a more detailed discussion on the components used on Decathlon 700 W.