tube amp for magnepan 1.6

I am currently using a ss Threashold 400a class A amp to drive my new maggies 1.6's, I have own this amp for a numbers of years . I am looking to use a Tube amp that would work with these speakers. I use a Blue Circle 21 pre and looking for a tube amp for the maggies that would give me the power that would bring out everything they have. Thanks