The synergy is there with either preamp (say an ARC 5SE and the LL2.1D - you do want the Deluxe version) and both are great choices. The 5SE is more resolving, has better image outlines (if you're into that) and slightly more articulation in the lowest frequencies. It also has a remote. Tonality with the LL2.1D is superb without being overly warm or rich. It sounds like a Lamm preamp which, as you know is very much in its favor. Fwiw, the LL2.1D definitely improves - and not by a small amount - with better 6DJ8 and 12AU7A tubes versus stock. Two great choices - imo you will not make a mistake with either choice.
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?