Of the list you provide, I would only choose the Nagra if you like a less traditional tube sound. My experience with Air Tight is similar to the Nagra. I cant comment on the Wavac due to limited experience. The Shindo gear is great for a more traditional tube sound and what Luxman I have heard errs to the pleasant.
But, in my experience, both push pull and SET designs are inherently somewhat flawed and in somewhat opposite ways. With the right speaker I have yet to encounter a better design than an OTL especially if you really want to hear what is going on with your software.
But, in my experience, both push pull and SET designs are inherently somewhat flawed and in somewhat opposite ways. With the right speaker I have yet to encounter a better design than an OTL especially if you really want to hear what is going on with your software.