I've had my kickback 12 for about 3 years and just recently it started buzzing, which increases with volume and treble. The sound is like distortion on a bad guitar amp, or the fuzz in between radio stations. It does this completely unplugged from any of my gear, so it's for sure not my bass or my pedal. It even does this with headphones in. Question is, how do I fix it? Also when I turn it on it makes a loud pop noise. And.. when I increase the volume while it's plugged into my bass the amp makes a crackling noise. These things don't bother me, just putting more info out there. The tone is fine, if you get what I mean. Bass, mids and other tones come through good, but there is that obnoxious staticky hum always in the background while I play. So it's kind of like nothing changed, but the buzzing was added with my tone.