The solution is simple to me - get rid of the cold cathodes. Note that fancy lights do nothing for performance, consume some power, generate some heat, and do nothing for performance (worth repeating!). Not sure about you, but I want my case to sit discreetly and quietly out of the way so I can pay attention to what's on my monitors and coming out my speakers.
Alternatively, you might be able to disable the offending port in HD Audio's control panel so it does not sense anything and hopefully, it will not mess up your sound. If you are convinced you need fancy lights, I would inspect all the cables and connections to ensure they are not damaged, then rewire them so they get their power from a different PSU connection and hope the interference they appear to be generating is isolated from your audio device.
