Another vote for the Lamm preamp. I think it will be a better match (sounded great with my ML 1.1s when I had to borrow one from my dealer while my old preamp was repaired). I think Jtimothya did a pretty good job describing the basic differences I hear between the two brands, and I tend to go for the Lamm sound over the ARC sound.
ARC ref 3,5 OR Lamm LL2.1 for my ml2.1
I have been using the AYRE KXR preamp for my Lamm ML2.1 amp. I recently tried the Lamm LL2.1 tube preamp and wad floored at how much more musical my system sounds now. Pianos sounded like pianos. Voice had the mid range magic. One of those great moments where a 7k box beats a 20k box. Now that i realize synergy and tube preamp - i wanted to test the ARC Ref 3 or 5 - anyone experienced this combo and any ideas about the difference between ARC and Lamm preamps on this system?