Bsevans -
The problem that a solid-state amplifier has driving the Sound Labs is related to the high impedance in the bass.
You see, the Sound Labs present a ballpark 40 ohm load in the deep bass, decreasing to around 6 ohms at 500 Hz, then going back up to maybe 15 ohms before gradually decreasing to 2 ohms or so at the very top end. (Before January 2002, that midrange impedance dip was down to around 3 ohms, rather than 6 ohms - which was much more of a challenge for OTL amplifiers. The reason for the two-hump impedance curve is Sound Labs use two transformers - one for the bass, and one for the high frequencies.)
I would guess that strapped Levinson ML2's do something like 100 watts into 8 ohms (not sure how the math works out), and double that into 4 ohms. But, what about into 40 ohms? Because solid state amplifiers act as a voltage source, the power delivered goes down as the impedance goes up. So into a 40-ohm load, a "100-watt amp" solid-state delivers about 20 watts, and clips way before you think it should. On the other hand, it will sound very good up until the point where clipping sets in.
Generally speaking, tube amps are better at delivering power into a high impedance load, so a high quality medium-powered tube amp has a better chance of driving the Sound Labs than a comparable solid-state amp.
Duke
