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. 

In this stage, the Athena Power AP-MFATX40P8 power supply is flawless. It has two Y capacitors and one X capacitor more than the minimum required.

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Figure 8: Transient filtering stage (part 1)

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Figure 9: Transient filtering stage (part 2)

On the next page, we will have a more detailed discussion about the components used in the Athena Power AP-MFATX40P8.