Steve has ditched the Nagra VPA and Modwright 36.5 pre and is now using this class A Vitus SIA-0025. 25 Watts in class A, or you can extend that from 25W to 100W by switching to class AB. At normal volume levels you can't hear a difference between the 2 modes, because it is probably operating entirely in class A. However, with the wick turned up on the 88DB efficient speakers, the appears to be a marginal improvement is the bass response in class AB. That is, marginal with one ear. Interesting.
Until we get there... just let it flow.