It seems a very nice piece of kit. I was amused by Gary Upton's explanation of impedance matching which he posted on his website today. Explains it all, I think. I've lifted this without his permission so I hope I won't get put on the naughty step:-
Imagine your pickup is talking French, and your amplifier only understands German. With lots of effort and wild gesticulating, the amp kinda gets the gist of what is being said...but it's missing the nuance and romance of the language. Enter the Pre-Amp! The pre-amp is the translator, and makes it so the amp understands everything the pickup is saying.