A masterpiece A-brick

That is a very high power density for how small that amp is at 50mm x 30mm. It is bigger than the photo in the PDF makes it look - by far that is the biggest inductor on the smallest amp. Looks like a self oscillation type circuit similar to IRS2092 except with feedback after the inductor. I wonder what honey sell for?

From CES booth - you can see once integrated into a motherboard with requisite filtering, dual rail supply, logic etc, the size is not any smaller than an equivalent 400w stereo LJM IRS2092.

[IMGDEAD]https://positive-feedback.com/wp-content/uploads/2015/11/roll2.01-022.jpg[/IMGDEAD]
 
That's not that small if you look at what a +/-44v rail class AB can look like (built by member borys):

http://www.diyaudio.com/forums/solid-state/96192-post-your-solid-state-pics-here-458.html

536075d1457377667-post-your-solid-state-pics-here-minicfp3.jpg


536074d1457377667-post-your-solid-state-pics-here-minicfp2.jpg


536073d1457377667-post-your-solid-state-pics-here-minicfp1.jpg


P=44v^2/4ohms=484w
 
A-Bricks or Audio-Bricks are now Ice-Bricks.
After a couple of years of "please enquire" they are now listed as available from profusionplc.com
ENGINE-400 Amplifier
AUX-PLANT DC-DC converter to generate the various voltages required and
MOTHERBOARD-1 If you don't want to design your own peripheral circuitry.
And you still need to provide a DC supply.