ARC ref 3,5 OR Lamm LL2.1 for my ml2.1

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.

You can use the exercise...go with the Lammie, no remote.

Dealer disclosure...

Cheers!

I've never heard a good Audio Research combination. Even at the high end spectrum.

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.

Lamm or Bust... Go with Lamm. I just added an L2 to my system over Dac to amp direct. No comparison. I say again, go with Lamm.