I have a pair of JBL N310s as my main speakers. I have a N Center and soon to have some N24s as surrounds. I have a JBL 250 Watt 12"sub (not sure of the model number). As of now I think my sub is broke. My receiver is a Pioneer VSXD811s, should I get an amp for the N310s? They each can handle 350 watts, I was looking at a Samson S700. Or for that $300-$400 should I get a new powered sub? Thanks for any help.