So I recently got a new bass head and cab (Ampeg pf-350 and svr-212) and when I'm playing on a concrete floor without shoes I experience a shock. It's not when I touch my strings with my fingers though, only really on my forearm. It's enough of a shock though that it feels like pin pricks. I have my amp plugged into a power strip that has an LED ground light that is on. My bass has active pickups but I've never experienced this before. What is the problem here? Do I have a bad amp?