Here is the manufacturers link for technical details:
From what I can gather it uses a MUSES 8920 op-amp input stage and discrete class A output stage. I haven't found any decent internal shots apart from what is provided on the manufacturers page but it appears that the output stage may use 4 discrete transistors (mosfets?) mounted on heatsinks similar to what's seen on the Audio Technica HA-5000 and Audio-GD SA-31. Those could in fact just be voltage regulators but it's difficult to tell without a better internal shot. Manufacturers rated PEAK output power is 1400mw @ 32 ohms.
The most interesting and unique feature however, is the adjustable damping factor switch to adapt to headphones of various impedance.
I suspect this could be a more affordable alternative to the HA-5000 for Audio Technica users but I haven't seen a single impression outside of one or two Japanese blogs. The current street price for this is about $800.
There is also a matching DSD USB DAC (for the same price) along with speaker amp and CD player in the 501 series, the DAC already having it's own thread here:
Since the amp has been out for a few months now, I'm hoping somebody has pulled the trigger on one and is able to share their impressions. The price doesn't seem too unreasonable for what it offers IMO, very flexible for sure.
Edited by JWahl - 1/13/13 at 10:07pm