I thought hard about the Kasandra Ref II, and wouldn’t totally rule it out if the right opportunity arises but I decided to be settled in with what I have for now. The solid state Merason DAC1 MkII stays powered up all the time so I mostly listen through it while using the Helene occasionally when I have more time to listen and want to warm up the tubes. The Helene is the better DAC in most ways but the Merason is very enjoyable to listen through as well. One thing against the Kassandra is that it is just too big physically. Although I could make it work, I would have to change my entire set-up. Another thing is when I ask myself the question, what problem are you trying to solve? There is really none. The Helene sounds so musical and tonally rich that I wonder whether the little bit of this or that the Kassandra might improve on is really necessary for my enjoyment. Besides, I could always add the Project X (Hronos) to the Helene. Aries Cerat say their new digital interface is like a full DAC upgrade, which would probably be more than enough. Also, the Hronos is very expensive, and about the equivalent cost of upgrading to the Kasandara Ref II.
The other DAC on my radar is the Imersiv D-1, a multi-path DAC (link). That would be much easier to add to my system and would likely take the place of the Merason, if I choose to add it. However, instead of trying new DACs, I have been messing around with streamers for now (link). Interesting, and relevant to this thread, I have been using AI to predict and verify the differences I am hearing between the Innuos Stream 3 and Sonore Signature Rendu SE Deluxe optical and, so far, the predictions have been pretty much spot on.