Hi, i have a Harman Kardon HKTS system and the sub is faulty, it keeps making a popping/cracking noise which when i rund them they belive the amp is faulty, its about £150 to fix or ive seen 2nd hand ones go on ebay for about £130-150 same with the Kef PSW2000, should i just get one of these or would it be worth looking at something