QUOTE(krabapple @ Sep 9 2008, 12:18)

IIRC, one physical limitation was in the ability of TTs to track very loud parts of LPs (e.g., the infamous cannon shots of the "1812 Overture"). I presume this is less of an issue with today's TT/cart combos, but couldn't say definitively, as I rarely use that technology these days.
It's still an issue for a lot of carts, but it was more or less alleviated by never hitting that level again

QUOTE(krabapple @ Sep 9 2008, 12:22)

Well, then, that means, as Hancoque said, that vinyl cannot be mastered as hot as CDs -- i.e., the hottest CDs will be hotter than any LP can handle, unless the waveforms are tweaked or level is lowered...in which case the LP is still not as 'hot' as the CD! I don't think he meant 'you can never master an LP at the level of a CD'. As long as the CD is mastered within the level range that LP can do, you can do a 'straightforward' transfer.
Well, yeah, but more fundamentally, "level" means something completely different here. Apples and oranges. CD "heat" means how close the signal gets to 0dbFS, and almost always is modulated through compression and limiting; vinyl "heat" means how high the modulation peaks are relative to NAB 0db (5cm/s?), and is almost always modulated through straight up gain.
As a matter of comparison, though, saying that a CD is "hotter" than the vinyl implicitly means that compression/limiting is being compared here, and not gain. The differences in gain between all the different components of the vinyl system are such that saying that the vinyl sounds louder/softer than the CD is sort of meaningless.