Yes, YOU. Clean your stuff! I was experiencing some crackling on some of the knobs on my mixer so I took a flashlight to it, looked closely and saw dust. What did I do? I opened it up. Off came all the knobs, unscrewed the bottom and had LOTS of dust. I should have taken pictures, but anyway here I was looking at a mixer with dust where I didn't think dust could go. I sprayed the hell out of everything with compressed air and did a lot of picking with tweezers to get as much as I could out of the cracks. With everything back together, the mixer sounds (and looks) much better. So my advice to all of you - next time you're bored, take the time to clean some of your gear, you might be surprised.