The BHK Signature 250 is the best power amplifier I had ever heard until the Signature 300 came along. When I was asked to audition the Signature 300, the stereo 250's mono counterpart, I expected it would sound better, but not by leaps and bounds. Not as if it had taken a whole new look at music and how it was reproduced. Yet, that is what happened, much to my great surprise, as I reported in this post. So now I want to start asking the questions many of you are no doubt asking. Why? Why should this mono amplifier defy all experience? It isn't as if we are inexperienced with amplifiers and their differences, yet the Signature 300 defies all that any of us would have expected: better separation, layering, soundstage, power and freedom of compression. And it has all those, but more. And it is the 'more' that I want to think about and start to understand what differences might have caused this to happen. Over the next few days I will start to detail first how mono amps are created from stereo amps, and there are several ways to do it. Next we'll look at what advantages and disadvantages each type of mono configuration has. And last we will think about what is fundamentally different about the 300 - and yes, it is fundamentally different than any power amplifier ever made.