Sorry to hear you're experience with the D500SE was less than satisfactory, 2x6spds. I have had one since August, and am happy to report it sounds fantastic in my system. I find the bass deep and tight, with clear, accurate and revealing mids and highs heard through my M60's. Of course, as has been noted in many previous posts, some CD's sound better than others, depending on how they were mixed/engineered/ recorded.
Was wondering if you allowed for the initial 36 hour "burn-in" Cambridge recommends, before you did any critical listening? What gear were you playing it through (I noticed in your earlier post you have quite the "audio arsenal")? Maybe you had the bad luck of listening to a unit that was defective?
Cheers.