They are still, however, a very nicely-made tube and I look forward to hearing more opinions on them. As for myself, early impressions surprised me somewhat, as the sound was quite different to the RCA 6DT6As, and after 20+hrs I still can't decide whether I prefer them or not. I think it could well be down to the extra soundstage/'3D' effect plus more detail. But at the moment I am wondering if this is at the expense of a certain degree of focus and coherence...Vocals appear a bit further in the distance, and to get the same hard-hitting bass requires more volume, which is not so good for my ears! Everything is so wonderfully 'clean' and clear, however, that I pray further burn-in will resolve such matters...Or that I simply need to get used to the different sound!
Whatever, I do hope more of you get the chance to try out these tubes and post your findings.
BTW - setting is EF95, no strap (don't know if any other is possible/adviseable...)
I think your understanding of what you are hearing makes intuitive sense. In a more 2D stage, everything is focused very tightly, right up against your face, so to speak. But in a more 3D sound stage, there is more space between the instruments, especially front to back, and therefore, some vocals and instruments do seem to be further away.
And yes, the setting is EF95. No other settings are possible or advisable.
And these EI tubes do look very similar to my Blackburn tubes, so it would seem very likely that they were manufactured in Yugoslavia using ex-Philips factory equipment. And perhaps they sound similar too.