I killed my speakers in such a foolish and avoidable way. My stereo preamp failed so decided to connect my speakers' amplifier directly to my computer; it sounded fine except I needed the pc's volume to be at 8%. It is a high end sound card, and I think it sounded better than before. Unfortunately I noticed that if the RCA cable connecting the sound card to the amplifier was disturbed then it would emit very loud pops of static. Only after both speakers' tweeters stopped working after a very loud buzz did I realize other current was coming across the sound card's metal. I first blamed the cable, then the amplifier but both work fine.
What can I do to reduce this leakage of electricity when I take apart the computer? I am going to replace the stock power supply at least. Is there a way to ground audio cable?