I haven't used a Neve 1073, but many claI'm there's magic in this combination of Neve preamp and eq.

Not wanting to spend the $$$'s for the 1073, but having a Neve 1272 and some open slots in a API rack, I was wondering if the combination of a Neve 1272 + API eq (550, 553, 554 type) would approach the "magic" of the Neve 1073?

..anyone know the difference between API 550 EQ and the 550A ?I know the 550B has 4 bands, whereas the first 2 have 3, but what else ?