The resonance in the LCD-2 seems to vary in severity between units, but it's not power or amp related. I heard terrible resonance/reverb (and might have heard veil too if the reverb hadn't kept me from listening to them) in my LCD-2 and yet have heard nothing like that in any other orthos, not even the 1979 Fostex T50, which has a driver of similar construction and similar size to the LCD-2, and yet is much harder to drive. I've heard a lot of orthos on this gear and never heard anything like that resonance/reverb except when experimenting with damping schemes and enclosures that did not work or were not ideal.
I didn't even hear anything like that when I plugged the HE6 prototype (harder to drive than the production HE6) directly into an ipod.
It's coming from the driver, pads, damping or enclosure.
Unless you think the LCD-2 has amp requirements that are unique among planar magnetics?