Howdy
I'm planning on making the attached BPA200 design with six 3886s.
I wanted the extra capacity to handle loads that weren't 8ohms all the time, or another way to look at it was to just give the amp a bit of extra overhead from the published design.
My layout was derived from the usual AN1192, and the front page of the 3886 design note, and from spending far too much time reading this forum, than actually doing it...
I chose the dimensions because 150mm x 150mm PCB board is cheap and easily available.
Obviously (I hope), this is only one "side" of the BPA200 design.
I laid out the board with the taller caps and components away from the chips, so that I could mount the chips to the heatsink using a spreader bar over the chips, to help squish them closer to the sink. I reckon it looks nice and symmetrical, but the purists amongst us won't like it because I put the power supply caps too far from the chips...

Perhaps mounting the 0.1uF power rail caps on the trace side could help...
I have put in components for a zobel network on each chip also.
The "zen" (or is that chi?) was ruined a bit by adding two 10k resistors and a header pin for connection to a Rod Elliot SIM board from the middle chip.
My plan was to drive the boards from a balanced output from a mixing desk directly, so I hope I won't need a buffer. That could easily be built onto an input board if needed.
My power supply will be a 300VA toroid, which I had to unwind from 30 to 24v, so your 500VA transformers will be perfect for a heavy duty 200+ watt power amp.
So, forum members, what do you think? I wish I could say I've built it, but I'm having trouble with the toner transfer method and the paper I have at home. I keep getting 70-80% transfer. I've printed it out on overhead transparency film, so that's my next move to try.
Also, instead of the 0.1r 5w resistor, what about using the LR network as detailed on pg 20 of the 3886 notes? This would provide extra amp stability. Would it achieve the same thing for load sharing?
Paul