"-the Luxman strikes that most elusive balance of transparency and musicality, successfully melding superior detail retrieval with a warmth and smoothness that encourages long listening sessions." -John Acton L-507uxII Review
The L-507uXII is the largest of the two blue-metered standard range class AB integrated amplifiers from Luxman. It's identical in dimensions and 5 lbs heavier than the L-505uXII. What you get beyond the L-505uXII is more power and current, better volume control circuitry, better interior isolation, lower distortion, and upgraded cosmetics.
The L-505uXII has 100 watts at 8 ohms, and the L-507uXII has 110 watts at 8 ohms. On the surface this does not sound like much, until you consider the L-505uXII has 150 watts into 4 Ohms and the L-507uXII has 210 watts into 4 Ohms. That means the L-507uXII delivers much more current than the L-505uXII into the challenging impedance curves of modern speakers. It's similar to four cylinder vs an eight cylinder car. They both accelerate ok in a straight line but go up a hill with passengers and the torque of the eight cylinder won't struggle.
The L-507uXII has the higher performance LECUA 1000 volume control which is similar to that found in the separate Luxman preamplifiers. This will give you better resolution, blacker backgrounds and a cleaner sense of musical drive. It also results in lower measured distortion, as you can see in the specifications. Compare the internal pictures of the L-505uXII and L-507uXII to see the latter's heavier power supply, larger heat sinks, and interior metal shielding partitions.
Cosmetically the L-507uXII gains polished aluminum input and volume controls, metal knobs, and machined chassis panels. Zoom the images and you'll see.