I also have a Luxman 590 AUii which I also enjoy but for different reasons. The pass is smooth as silk and fuller. The Lux is more detailed with huge dynamics and just sounds so effortless.
This is useful. I believe it's the Luxman L-590AXII you are referring to. It appears that your impression on the Luxman coincides with Steve as well. The 590AXII was said to be more detailed than the Pass.
Luxman 590 AXII – Sweet, a little leaner than the Pass Labs with more detail so this is more for those who crave sharpness and detail over warmth and liquidity. Class A 30 watts but what it lacks in body compared to pass it makes up for in sweetness and dynamics. Made in Japan.