I'd like to thank
@kdude66
and
@grannyring
for their recommendation of the Lyngdorf 2170. I have been following the Tekton DI thread for a long time, and it was there that I was convinced I needed to give one a try. Needless to say, I have sold off my amp, preamp, DAC, and various cables/power cords and am extremely happy with the 2170 (and pocketed a decent chunk of change as well, which the wife will put to good use!). RP is the real deal (I was a total skeptic). It is so effective at integrating a sub into the system that I now run my sub all the time (don't really need it with my mains, but seamless integration).
I have mine integrated into my home theater, and it works flawlessly. Any analog input can be set up as the bypass input, and it also has a 12v trigger input -- makes it easy for my wife to watch movies -- push one button on the HT receiver and everything is up and running. I found the best results with setting the xover for the sub myself in the 2170 and then running RP. I would also add that using the 2170 all the way through is the way to go. I tried it with external DACs and amps, and always came back to the 2170 alone. And as has also been mentioned here, the volume control is awesome. I have extremely efficient speakers, and have always been forced to run preamps at very low, non-optimal settings. Wish I had the guts to do grannyrings upgrade -- don't think I am good enough with precision soldering (have rebuilt some speaker xovers, but precise soldering is not necessary there).
@kdude66 , I have not yet taken the plunge to the DIs from my Zu Definitions. Was thinking hard about it, but the Defs with the 2170 is really, really nice. Again, thanks to all who contribute to these threads -- so informative and helpful.