I've had my 90-something Peavey Fury for just over 2 years now. I've always played through a small like 35w Samick amp. A little while back I joined a gigging band and bought an Acoustic B200 200w combo amp. Since getting the larger amp I've noticed a static-type hum coming from the bass when I don't touch it. When I touch the strings it stops. A grounding problem, I know. But I've racked my brain trying to figure out where. Here's where it gets interesting. Today I got a new pre-wired pickguard and went to install it. The pickguard didn't fit my bass body so I took all the hardware out and replaced it onto my existing pickguard. So the issue is: brand new pickups, brand new pots, brand new jack, all wired correctly. When the noise still happened I tried different cables, still did it. I plugged a guitar into the amp, nothing. So I know it's in the bass somewhere. I pulled everything apart and tried different bridge grounds and it still did it. Once the bridge is grounded the noise lessens but when I touch the strings (or anything else metal on it) it stops completely. Turning down the highest EQ knob on the amp helps kill it too, naturally. I just can't figure out what the problem is. Any ideas?