I've owned K8's and wouldn't trust their 2 ohm dip and phase angles to tubes. Sloppy bass. In your budget, look at an old Aragon 8008 (BB being slightly better than ST) or McCormack DNA series.
I know that Infinity used an ARC tube amp for reference/voicing but not for the Kappas.
I know that Infinity used an ARC tube amp for reference/voicing but not for the Kappas.