So my Yamaha SW315 quit working and after checking it I believe it is the amp. I'm on a limited budget and don't want to spend more than $150. Should I replace the amp with the Dayton SA240 plate amp http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=300-804 or just buy the Dayton Sub120?http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=300-635