Tannoy D700, 500 How do they sound?

I have only heard the D700 at a dealers and so will not comment directly on the sound. However, the reputation of these speakers is that, despite their efficiency, they present a reasonably difficult load and need lots of current to control those big cones. Some say SS amps, or very good and powerful tubes. This might end up being a problem for you with only 40W of tube power. Otherwise my brief listen suggests they might fit with your desire for "smooth, fun, dynamic, deep tight bass".