It's very strange that you're finding the bass thin on the Towers. When I built mine, the first thing I noticed was the incredible dynamics. The second thing was the bass. In some recordings, it was enough to buzz the windows in the room. Definately check the phasing as Wayne suggested. Mine were always able to fill the room up with bass.

And yeah, revealing speakers and poor recordings are frustrating. At least you got a set of good component to drive the speakers. BTW, have you soldered the CDP and amp together like I suggested to hear how it can sound without IC's

gar.