I've recently started having issues on my spider iv 120 amplifier. No matter what mode I'm in (manual or a preset) it has this problem. The first effects knob containing the smart harmony, gain, and autowah turns itself on. Say for instance, I turn on the amp, and start jamming and it's just fine. But if the knob gets touched or the amp is up loud enough to vibrate at all, any one of these effects on this knob randomly comes on. Most of the time it's the auto wah or smart harmony. Even if the knob is put in the off position, or if i have my preset saved with no effects. It does this on any preset and in manual mode. When I turn the knob back to off and let go, it just jumps back to whatever effect it decided to turn on itself. I've never seen a spider act this way. It appears to be an issue with the knob. But I don't know. If anyone could help me with how to fix this, it would be greatly appreciated!