Nice write-up on the 550, Steve. Great photos, too. One thing I'll mention, and can't offer any first hand knowledge, but for whatever reason Luxman understates the power on these (or at least the L-590) and pretends that they're solely class A. From tests I've seen, the L-590 actually puts out around 90W/channel @ 8ohms, contrary to the claimed 30W, presumably switching to AB at some point. I assume the L-550 is no different.