Aragon 8008 BB, high current. This seem to have been the choice for powering the Kappas in the beginning. They go for about 1000-1200, and if you can get two, you can biamp them with the Infinities. BTW, I have a pair of Kappa 9s in storage, at my mother's place and they do sound GLORIOUS, especially in the bass. I have a McCormack DNA 225 and when the time comes to move them over, I will get another amp to play with the biamping set up.