Grounding issue?

**TheDude007** · #1 10-20-2010, 09:44 AM

I have no idea where this goes, so I'm putting it in Misc. Ok, I know grounding issues have been discussed quite a bit on TB, but I think this might be a unique circumstance. So last night at practice we got all set up, and I kept getting shocked via the mic. So, we tried swapping the mic cable. Still got hit. Swapped the mic. Still got hit. So I said screw it, I'll just make sure to stay back from the mic tonight, it must be something in my bass. But then, about halfway through practice, it wasn't doing it anymore, and didn't do it the rest of the night. I checked my ground wire in my bass, and it is secured. Does anyone have any idea what might have caused this, and how it miraculously fixed itself?

**TheDude007** · #2 10-21-2010, 09:00 AM

Bump? Anyone got any idea?

alembicguy · #3 10-21-2010, 09:04 AM

Not sure what your setup is so it would be hard to nail it down,could be a polarity issue or a grounding issue with power not really sure,what type of amp were you using,were you standing on concrete?

Bassamatic · #4 10-21-2010, 09:23 AM

That is often caused by your amp and the PA being connected to different AC sources, and one of them is reversed (socket miswired). This happens ALL the time. Every band should have a plug-in AC tester to show if the ground and polarity are good or not.

Why it changed? Someone moved or bumped something between sets, maybe?

Foam windscreens are a good thing to carry to protect yourself.

**TheDude007** · #5 10-21-2010, 09:40 AM

Oh yeah, I guess I should have mentioned that. Here's the setup:
Squier CV Jazz > Korg pitchblack > Bass Big Muff > Phase 90 > Memory Boy > GK MB 212

Someone I talked to mentioned the whole miswire thing, however, we've been practicing in this place with everything plugged in the same way for the last 5 years, and it's never happened before the other night. Oh, and the room is carpeted if that makes a difference.

Bob Lee (QSC) · #6 10-21-2010, 12:28 PM

Make sure your amp and the PA are grounded, through the safety ground prong on their AC plugs.

Even with everything properly grounded there sometimes may be a volt or two of difference in ground voltage between the chassis on one piece of gear and another; this is normal and not dangerous, though if your lips touch the mic screen you might feel a slight sensation but not actually a shock. To reduce the differences in ground voltages, plug the gear into outlets that are not separated by long amounts of wire; IOW, adjacent outlets would be good.