Search the treads there are a lot of answers to your questions....... With regard to the Carrissa; I would stay away from 845 valves with the AVG's. If you can find an Art Audio PX-25 that would be a great match- it is by far the best I have heard in my system (they even make a low voltage AVG model). You might also look at some of their 300b amps......
Chris
Chris