I can only speak to the Lamm gear I have owned and played in my system for extended periods. The two amps were used and the LL2 Deluxe preamp was purchased new.
Both the M1.1s and M1.2 Ref displayed nice body and dimensionality compared to most SS offerings. Both displayed a very big, full bass, which some would argue is closer to what you might hear live than the overly damped bass you get from some SS and from the NC1200 Class D amps I owned. The M1.1s were dark, dark, but smooth like syrup up through the midrange, and rolled off in the high frequencies. They made most music sound good and as my first venture into Class A, after a pair of Cary CAD500MB (500wpc) monos, my impression was that of comfortable music that sounded better than any stereo system I had owned previously. Eventually, I felt something was missing in the high frequencies and tired of the darkness so I moved on to a series of Clayton Class A amps.
I ended up owning the M1.2s at the same time as a pair of upgraded (power supply upgrade) Clayton M300s. I would only keep one or the other so it was a tough decision. I wanted to like the M1.2s better, because so many said the M1.2s were at/near the pinnacle of SS or hybrid amplifiers. I tried Amperex 6922 PQ, Electro-Harmonix 6922 EH Gold Pin, Mullard ECC88 / 6DJ8, and Amperex 7308 USA Gold Pin tubes I had sitting around from some preamps I used to own. While the tubes changed the flavor slightly, the basic sound remained the same. The M1.2s were not as dark as the M1.1s, and they did better in the high end. The bass was similar but maybe tightened up a bit. However, the Claytons were smoother throughout the entire frequency range and had just a bit better combination of fullness and grunt in the bass. To the points made earlier, I wouldn’t call the M1.2s hard or etched, but they did have a touch of graininess in the upper frequencies that was not present with the Claytons (maybe MOSFET vs. Bipolar transistors?). OTOH, the Claytons could not quite match that bit of magic in the midrange, but they came close. The Lamms were also a bit more dynamic than the Claytons from the midrange up, until they would run out of gas, which they did when pushing the Aerial Model 9s I owned at the time. That power discrepancy is the main reason I kept the Claytons and sold the Lamms, because otherwise IMO they were on par with each other, just different strengths.
The LL2 Deluxe preamp while being a fully tubed design did not display the stereotypical sounding warm tubed preamp signature. In my system it sounded clean, powerful, and properly extended at the frequency extremes, with very nice dimensionality. I stupidly sold it because it did not have balanced outputs (the Claytons only accepted balanced inputs) and I do miss what it was capable of in my system. I wouldn’t go back because of the absence of a remote/display and because my SMc pre does what I need, but I do miss the sound - highly recommended. If I had easier to drive speakers at the time, and didn’t mind the absence of a volume display and remote, the M1.2s along with an LL2 Deluxe would have made a great sounding system, IMO.
