I have a sub that only needs 2250rms @ 0.5ohms. I saw this MA Audio HK-802SX 2 Channel Car Amplifier (4400 Watts), it has 2200rms @0.5ohms X 2 channels, can i use just one channel on the amp? And is this a good amp for a sub?
If you're never going to use the other channel, don't get the amp. A monoblock amp will be more efficient and you'll get a much better amp for the price of that MA audio. BTW, never used that brand, but it doesn't have the greatest reputation.