pk_LA´s system is clearly a very impressive setup and I am sure it sounds wonderful. However, in the comparisons you have made, I am still a bit puzzled by your notes above.
When playing on a system, we do not listen to individual components, but to the entire system. By swapping components, as you did, we can listen to how individual components influence the listening experience of that particular system. Individual components may hide or emphasize positive or negative qualities in the system and I wonder if that is the case here.
I have not heard the Boulder 3060, but I have heard a number of other Boulder amps and in particular the 3050, since I almost bought it. They have all been great amps, transparent, analytical, dynamic, but, in my view, a bit on the dry side. Combining a tubed DAC, as the Lampizator, to a Boulder amp, may well be a match made in heaven, whereas a dCS Vivaldi stack may double up on some of the amplifiers edgy qualities, giving the results you are describing.
Like you, I am primarily an analog man and it took me a long time to embrace digital. It actually did not happen until I heard the dCS Vivaldi 2.0 in a Pass Labs and Martin Logan system. Currently I am using the dCS stack, but with an Ypsilon VPS100 MkII and Hyperion amplifier chain. Candidates I ended up with, after assessing them along side d´Agostini Momentum and Boulder 3050. I decided on the Hyperions, because they, combined with my analog rig and the dCS stack, gave me the most musical and satisfying combination. Dry, sterile, flat and thin are words I definitely would not use to describe it.
My experience with the dCS/Ypsilon combination is that it is the most musical and "analog" digital audio chain I have ever heard. Some of your descriptions above, and I am not questioning your experience, are totally wrong up against my experience. Based on my own listening, I believe it has to do with the Boulder/DAC experience, where the Boulder/Lampi were made for each other and not so the dCS. However, you made me very curious, so I will now try to get a Lampizator into my system and see how it works there.