Thank you for taking the time to do such an excellent and very comprehensive review that one can only expect from Audioholics.com nowadays.
My only suggestion now is, if you can please press D&M to at least tell you the VA rating of the transformers under review. I know they won't publicize such details as nobody does, but they may be willing to disclose it for the units you tested (still think it is a long shot but no harm trying). The 835/750 VA you mentioned for the 8012 and 6400 are directly translated from the power consumption thing, and that's cool too if we know for sure what those power consumption figure really mean but I don't think we do.
As an example, the older Denon, such as the 4308 has the PS specified in current, 8.1 A, so if we follow the same rationale, that is, to assume transformer rating = power consumption spec, it would be 8.1X120 = 972 VA, so compare that to the bigger and have more channel 8012, the difference between W and VA could be quite significant and would indicate the 4308, or even the old 3805 you also reviewed have larger transformers. Again I do understand this does not mean much or anything at all to the non technical audience, we are both EE, so I think you can understand how some of us think, we just can't help it.
Lastly, I just upgraded from my Marantz AV8801 to the Denon AVR-X4400H, but you have already reviewed the X3300W, so I would rather see you review the AVR-X8500H next time, if that's not too much to ask.
