I’m a huge fan of Atmasphere too, but you really need to commit to going fully balanced to get what their gear is capable of. Also, I’m not sure you should limit yourself to a certain tube type. Rather, it might be better to just identify what sound characteristics are most important to you and what improvements you’re looking for and just let that be your guide. That said, what are you looking for?
I’ve got the upgrade itch
Thinking about going back to separates. My current setup is a Primaluna Dialogue Premium Integrated amp. Since the Primaluna has an HT input, I can do the upgrade in two steps, upgrading the preamp first. I am thinking about a 6SN7 based preamp, such as Sachs, Supratek, or, an Atma-Sphere MP-3 (if I can stretch the budget).
Question, will the preamp switch make a big difference over the preamp stage in the Primaluna??