I am using an ARC LS25 MK1 with fantastic results. This preamp is a very good match with my JC-1's, from both a technical and sonic standpoint. I had been using an ARC SP16L which is SE only.
Switching to the LS25 and running XLR IC's between preamp and amps, has made one of the most significant improvements in my system. I've said it here before, if your not running these amps in balanced mode your not tapping their full potential, it's that important.
There are many improvements, but one of the most noticable is the "weight" behind the music is increased substantially, which makes listening at lower volume levels very realistic.
Your system will go from good to great.