Well, the whole system is really starting to grow some hair. Mid range is so smooth and rich that I just want to listen to Dave Brubeck Quartet's Time Out on repeat over and over. The system has never been so "listenable", and now I wonder why the previous bright, crystal clean, digital sound was so appealing. I'm really appreciating the added midrange warmth that seemed to bring back a quality of reality that was missing before, as opposed to just pure digital accuracy. The new audioquest digital cable (in combination with the Cardas posts) is producing the biggest stage I've heard from my system, and considering that was one of its strengths, that means something.
I installed the new Cardas posts using silver bearing solder and they are working great. Not a huge difference, if at all, but it's good having some nice posts in there after breaking the others. After I installed them I thought I had screwed up badly because there was an audible hum right after I hooked everything back up. After a day or two of experimenting, I narrowed it down to the cable tv wire, ugh. Looks like I have a ground loop so I got a DC filter from radio shack which seems to have fixed it (or it was a transient problem). The hum is gone now, in any case, and things are sounding amazing again.
I think the addition of the awesome MSB Link III DAC w/PowerBase was really the main factor in improving the sound, adding the really airy and pure midrange that was really missing before (people breathing, horns, and voices sound real enough to be startling sometimes), and the audioquest digital cable widened the stage. It's really pretty amazing how much a good DAC can make a difference, I'm not sure why they're not always sold separately. DACs in most CD players are crap, and to buy a CD player with the same DAC (24/96 Burr Brown) as the MSB would be more than double the cost of the Link III. Of course, there are even better ladder DACs that I have yet to hear, but that one is around $5k just for the DAC.
It seems I was on a quest for pure digital accuracy and clarity but, unbeknownst to me, it was at the cost of this incredible musical listenability. Of course, by that I mean that now I never want to turn it off or do anything else but listen, and before I would get fatigued relatively quickly.
Oversampling the MSB DAC to 133KHz also makes a notable improvement over regular 44.1KHz (no overheating yet), good thing I replaced the switch that controls the upsampling (which I had broken almost as soon as I got it). After talking to one of the MSB guys, who told me the switch was generic and I could get one at any electronics store and have it put in, I put in a heavy duty switch so it doesn't bend all out of whack again when I lean it back.
I'm having fun doing minor hardware modifications, and everything is better than ever!