Hi   In my Beovox C40, which sound terrible, the filter elco capacitors are perhaps the cause of that. So I want to replace them and notice they are no bipolair types but regular elco capacitors. Is that standard or did anyone replace them before wrongfully? Is there any other cause that could have an effect on the sound quality which is as if a blanket is on top of them. Btw the speakers look fine, no damages.