I nominate a nice euphonic amp like the WA22 (optimized for the HD800 with whatever tubes Skylab wants, he's working on it now), and the Liquid Fire with stock tubes (to make it fair price-wise at least) for the LCD-2. Since one amp is SE and one is balanced you could use the same source at the same time. Opinions vary but there aren't too many amps on par with these two for these two headphones, I think there is some consensus on that. It would also be fun to use a few different balanced DACs for comparison, but something like the W4S is developing a good following so that would be great for a start. Don't forget headphone cables, with modular connections the same ones could be used on both cans to eliminate that variable or each headphone could be optimized with different cables. So I agree that both headphones could be compared while optimized with separate amplifiers, but ideally it would be within the same "setup", sharing the same front end.
Edited by grokit - 6/4/11 at 8:52am