I have used Atma-Sphere MA-1's on the both the tweeters and woofers of the CS2's with very good results. I have also used a McAlister PP-150 on the tweeter. So tubes can definitely be used with the CS2's.
The best combination I have tried to date is running a Spectron Musician 3 MK II SE amp on the woofers, with the Atma-Sphere MA-1's on the tweeter.
The issue with using tubes on the CS2's is that due to their sensitivity, they will easily pick up any noise coming from your tube amps. A little hum or buzz that would never be noticeable on a high 80's low 90's sensitivity speaker, can be VERY annoying with the CS2's.
As for the preamp, can't help too much there as I don't use one with my highly modified and upgraded DCX. However, I do recall that Clayton used the Modwright LS36.5 tubed preamp at RMAF 2007 when I first became enthralled with the CS2's...
George
The best combination I have tried to date is running a Spectron Musician 3 MK II SE amp on the woofers, with the Atma-Sphere MA-1's on the tweeter.
The issue with using tubes on the CS2's is that due to their sensitivity, they will easily pick up any noise coming from your tube amps. A little hum or buzz that would never be noticeable on a high 80's low 90's sensitivity speaker, can be VERY annoying with the CS2's.
As for the preamp, can't help too much there as I don't use one with my highly modified and upgraded DCX. However, I do recall that Clayton used the Modwright LS36.5 tubed preamp at RMAF 2007 when I first became enthralled with the CS2's...
George