LP playback is lacking - any ideas?

Standing waves(bass) can make a system sound lifeless,small, congested. The gear you have is capable of at least 80%, of state of the art performance, if properly set up. Tube traps would be the fix, for that problem. DIY traps are very easy to make.

Could be anything -- dontcha love it? If the arm is set up properly, then I'd be tempted to look first at what is supporting your TT (you don't mention that) room as a likely culprit. Of course, if your CD player produces a similar kind of congestion, I might suspect your room.

Oops, strike the word "room" in the second line, above. I just mean what your turntable is sitting on.

Have you tried any premium vintage audio tubes? The most transparent, and dynamic sounding, are the Siemans. Tubes are the most critical element, in well designed tube gear. This is only the case, if it's only your LP playback, that is lifeless.

/