I should also have mentioned in my configuration in the original post that I also use a custom made XLR that lifts the ground to remove a hum. If you want the details on that see the last few pages in this thread:
http://www.hometheatershack.com/foru...d-bfd-hum.html
Not sure if this makes a difference and could have opened up a possible vulnerability leading to the amp's failure or not - but in another thread I read something that made me think it may be important to have mentioned this...