Luxman 507/509

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I chose the 509X and am not disappointed. Have not found official publication of the class-A bias but based on comparison of the idle power consumption to the 590 & 550 integrateds, I think the 509X is about 17 WPC class A and the 507 about 9 WPC class A. 

I asked Luxman USA in an email about the Class A envelope for the new L-509X(which I bought) and the L-550axii I was considering

Here is their response that I got:
" The Luxman L-509x is an excellent amplifier. It is considered “top of the line” and most recently introduced Luxman integrated amplifier model. It features circuit and construction details/refinements not present in (earlier introduced) the L-550aXII and L-590aXII.

L-509x is biased such that the class-A operational envelop approaches 6 watts/channel into an 8 ohms resistive load. At lower (or higher impedances) class-A operation transitions to class AB at lower output. (i.e. near 3 watts/4 ohms resistive load)".

@erikt 
Very interesting lower than expected class A bias. Thanks for sharing!  I wonder what all that idle power is doing if not class A bias....

@martinol 
Looking at the pics with lids off, the L-509X has twice as many power supply caps as the 507. This might enhance bass slam, and the 509 is not lacking bass slam in my experience!

The two areas where Luxman steps up/down seem to be power supplies as well as output transistor pairs. The 509 with 4, 507 with 3, and 505 with 2 pairs per channel.

I find the 507 to be quite splendid with my current setup. :)

Just to say thank you very much for your answers, very helpful!

OP -- you should consider the 550 and 590 models as well. They are quite similar to 507/509, but IMO add a bit more warmth and texture to the sound owing to their ability to operate in pure class A further than the other models.

Martinol, if possible please audition the 509X and 590AXII (or 507) with your Dynaudio Heritage. I find the L-590AXII to sound splendid in my system with Marten Duke 2. The Class A of the 590AXII imparts a slight warmth to the sound which gives an organic and real feel to instruments and human voice without sacrificing too much slam and dynamics. It's a rather neutral sounding amp.