Well, if you still need 1400 @ 8 ohms, I would go with what you can find that's in your price range. Crap, even a macrotech 5K will only get you 1K watts into 8 ohms. And that is a BIG amp lol.
Personally I wouldn't send 1400 watts into an 8 ohm driver, (assuming a horn loaded sub-single driver) sounds like a recipe for burning voice coils to me
And when I say burning, I mean on fire.
Personally I wouldn't send 1400 watts into an 8 ohm driver, (assuming a horn loaded sub-single driver) sounds like a recipe for burning voice coils to me