I've got a little noise in my system that I'm trying to understand and mitigate if possible. Guitar is SE Hollowbody II Piezo, using MAG output to Effectrode Blackbird preamp, and headphones from the preamp. I believe I have 60hz 'hum' as well as a 'buzz'. Both noises go away when I roll down the volume on the guitar, and both are louder with higher gain. The buzz goes away when I touch anything that's metal: the strings, the plugs/jacks, a footswitch button on the preamp, etc. I have a tuner, overdrive, and cab sim at the moment as well. I removed everything but the pre from the chain and still had the noise, and if I remove the pre and use everything else, it's quiet. IDK if that's because the problem is the pre, or if it's just amplifying the noise (4 stage cascading gain). The overdrive is new so I haven't tried high gain direct to the cab sim yet. Some amount of noise is 'normal' correct? Or is it realistic to expect a completely quiet system? Any tips to help diagnose? Thanks! Edited to add that I'm using a power strip that has a couple USB ports on it. Tonight I'll try with the pre straight into the wall and in different locations of the house.