The NAP 500 delivers 140W per channel into 8 ohms and is capable of prolonged output into 2 ohms with no discernible impact to performance. Its two box configuration is classic Naim Audio, with the power supply completely removed to the separate 500 PS power supply for ultimate performance. Each channel of the NAP 500 includes ten stages of local regulation. To reduce interference from the mains supply further, the transformer and first stages of the power supply are in a separate enclosure, the 500 PS, which provides twelve raw D.C. supplies for the power amplifier.

A bridged configuration allow for maximised open and closed loop speed, less intrusive protection circuitry and reduced interaction between input and output signals as the very high drive currents to the loudspeaker do not flow through the system earth. The NAP 500 also features the new output transistor, the NA009, specifically designed for the purpose through months of collaborative work with a specialist supplier. The circuit topology has been developed to maximise bandwidth and reduce distortion and power supply dependency. Also, special attention has been paid to reducing thermally-induced noise, an especially important consideration in power amplifiers.