Just got back from my short spring break vacation and have been doing some more listening. My Russian 6N3P tubes have arrived, so I will try them in the Paradisea+ soon.
FauDrei, you could wait for one to show up on E-Bay or contact them by e-mail and ask to buy one (not sure if they do that).
Just before I left, I had postulated the differences between the Paradisea+ and the USB+ Constantine. Coming back from the vacation and hearing it again has just further confirmed my initial impressions.
This unit has more detail, this being the most noticible. I can notice much more subtleties, and it has taken my system to the next level. The mid range has come alive!
In addition, both vocals and instraments seem to be more focused in space with a better sense of depth than the constantine+. Again, all this with the stock GE 5670w tube and optical out of my laptop Audigy 2 ZS sound card.
You know an upgrade is truely worth it when you can revisit your music library and it's as if you are listening to the music for the first time again, hearing new things and getting more personal with the music. This has been the case with my upgrade from the Constantine+ to the Paradisea+.
As others have said, the constantine+ can be had for about 260-350$us, and the paradisea+ goes for about 600$. Is it worth the roughly 300$ price increase? If you have the money to spend, yes! If you are on a tight budget then that question becomes more pressing, and the constantine+ is a great choice for those who don't have the funds for the paradisea+.
I highly recommend this for people who use their computer as source, or those who suffer from a cheap DAC in their audio players.
When I go back to school, I'm going to do some serious comparisons between the Paradisea+ and Constantine+ back to back, but I already know I'm sticking with the Paradisea. Now.... I have to decide what to do with the constantine.