Impact of Calypso 6922 tubes?

I am trying an Aesthetix Calypso preamp. This is a newer unit with no noise floor issues whatsoever, and the stock tubes are very quiet. I tried replacing the stock 12AX7's with a nice pair of NOS Brimar tubes I had sitting around and heard noticably more body and a richer tonal presentation. To those of you who have this preamp, have you noticed similar changes when using NOS tubes, and would I be likely to hear similar changes if I were to replace the 6922 output tubes with NOS?
So how does the Calypso compare to the Tom Evans Vibe?
Sorry to ask you a question rather than answering your post.
It is a little early to say. Upon initial listen, the Calypso is very good, as I expected it to be. I like the bass better than on my (previous) decked out Atma-Sphere MP-3, and the whole presentation is clear and dimensional, but it is a different sound compared to the organic and vibrant sounding MP-3. Comparision to the Vibe is more difficult. They are both excellent, and each seems to have its own strengths. I cannot yet say which I will keep, and I do not believe I yet have the full measure of the Calypso, so maybe I will be able to comment more specifically after I listen some more.
Mitch, I have owned the Calypso for about a year now, and think it is stunning. It replaced my ARC REF II mkI, and I've never looked back. In my experiences with tube swapping I settled on Ediswan 6922's and Telefunken 12ax7's. I actually liked what the Ediswans did for the sound better than what the tele's did. The eddies are very smooth with an incredible mid-range. I also plan on experimenting with the Mullard/Brimar BVA 12ax7's very soon. Please let me know if you have any other questions. I hope this helps.