The L-550AX is a solid-state integrated amplifier to incorporate a truly lossless volume control and superior audio circuitry. With an illuminated central oriented VU meter in its solid, symmetrical front fascia, the L-550AX incorporates the LECUA 1000 high precision electronically controlled attenuator, the latest ODNF 3.0A audio circuit and custom passive components as used in Luxman‚¬„s flagship C-1000f control amplifier and B-1000f mono power amplifier.

The LECUA 1000 attenuator is configured to electrically block electromagnetic (EMI) and radio frequency (RFI) interferences. The output signal is attenuated without introducing artifacts inherent of conventional volume controls, thereby resulting in constant output impedance, high signal-to-noise ratio, a uniform frequency response and lowered distortion. As its name implies the ODNF (Only Distortion Negative Feedback) only applies negative feedback where distortion is present to reduce colouration more effectively.

This lossless audio circuit enables the amplifier to retrieve every musical nuance captured by recording engineers. Transient response, attack, dynamic contrast, timbre, inner detail, and bass authority are preserved.