Thanks, Peter, for coming over and for your impressions. It was a fun session indeed, but I agree, also confusing.
As you say, the differences between the DACs are relatively minor, at least on this violin recording (which we spent a long time on with comparisons). We didn't play a recording with much bass, where I think the differences are more pronounced, in favor of the Yggy. Interestingly, it now seems after all the long break-in drama with the Yggy that my first impression is confirmed, that the differences between the DACs are not that great. After the session I realized that in part the differences might be caused by the different power conditioning as well (the Berkeley running at 230 V on the Tice Power Block II, the Yggy on the, also over-dimensioned, Tripp Lite medical-equipment grade isolation transformer). -- I did not have the footers (Herbie's Tenderfoot) last time and I put them under both DACs for a level playing field (also literally; both DACs wiggle a bit on their own feet which they shouldn't).
We also listened to both DACs through the Pass B1 buffered preamp, something that Ack pointed out as beneficial for the Berkeley, and this time we both could hear that the sound of the Berkeley (set at output level 54, as manufacturer recommended) was more open through the Pass B1 than going direct. We made the same finding twice, the first time going from DAC direct through Pass buffer, and later on in the session going the other way around. You also pointed out (which I could not hear, sitting off center) that with DAC direct there was an artificial effect to the soundstage where the sound came forward from the violin as if through a funnel. It was definitely a good thing that the acquisition of the Yggy forced me to buy the Pass B1; it also had the indirect yet of course highly important effect that ultimately it made me buy new cables because I had to change lengths. When I first did the comparison DAC direct vs. Pass B1 I could not hear the differences, but at the time my system was also less transparent than now with DaveC's outstanding ZenWave Audio cables.
While we agree that the differences between the DACs were minor, at least on the violin recording and on the briefly listened to piano recording, I am not sure I fully agree with the characterization. I thought most of the time that the Yggy sounded more lively, but at one point I agreed with you that it did sound more bland and whitish (an 'OMG moment' at the time). But then I lowered the volume just a little bit (because I thought perhaps this time it had been just a bit louder), and upon replay I thought again that this was not the case and I preferred the Yggy once more -- one of the moments of confusion during the session. It is clear that our session confirmed how critical it is to exactly match volume, to the extent possible.
The Yggy does slightly emphasize the upper midrange over the Berkeley, which on this particular recording may have caused you to perceive the Yggy to sound more whitish. At the same time I think that overall, over a number of recordings, the Yggy also has more body in the lower midrange (including on the piano recording). It just sounds more extended to me in all directions; yet again, apart from the bass, the differences are rather subtle.
In the bass the Yggy performs clearly better in my view, with more weight, slam and definition, even though the Berkeley is already excellent in that area, in absolute terms and compared to other DACs, as also FrantzM once pointed out. It's just that the Yggy is exceptional in the bass, as Robert Harley describes in his review as well.