Insane Possibly Dangerous Problem

[JSRocker]

Ok, I was at practice a week or so ago. I was playing and singing, and I brushed the mic with my lip as I sang. It seemed as though there was something sharp on it, so inbetween songs, I felt it, rubbed my hand all over the windscreen, but nothing. Anyway next song, I bumped the mic again, and this time I noticed that it was not sharp, but instead, electrified. It shocked my FACE! And it hurt!

 

Next practice, I asked our sound man about it, but he couldn't find anything wrong, and it didn't shock me either. I thought it was just a freak occurance.

 

Anyway, last Tuesday, I was practicing again, and it blasted my face AGAIN. And then it got my nose! I had no idea what was going on. I asked the bass player to come over and check it, but he didn't get anything. I touched it again, but nothing. My guitar neck was getting in the way of the mic stand so I reached to move it out of the way... ZAP!

 

If I touch the microphone with my hand on my guitar strings, it shocks me. Really bad. What could cause this? My guitar is a 6 month old Schecter Omen-6. I have extended warranty on it as well. What do I need to do to fix this, and protect myself? I know it's the guitar, because this has happened three different times, with three different PAs Mics and Cables.

 

Thanks!

[FUBTAG]

Not guitar.. your amp!

 

You were part of a ground loop.... could be dangerous if you let it.

 

On your amp, use a ground lift .. the little adapter that you connect your 3 prong plug to before insertign it into the wall or strip. I get this (never died...) and I corrected it with this.

[zerkalo]

Wow, I've never heard of this problem before. Can't help ya, but good luck.

[gtrjones]

I believe what's happening is that your guitar amp is not grounded well, and when you touch the guitar and the mic, YOU're grounding the amp to the PA.

 

Check the plug/grounding on your amp.

[JSRocker]

Ground Loop?

 

I knew it had something to do with grounding...

 

Do you mean one of those things that you use to plug in three prong things to outlets with two prongs?

 

I was pretty sure that all three places this happened has grounded wiring... but that may not be the case. They have three prong outlets, and I know the round one is supposed to be a grounding prong.

 

Is this a problem with my guitar amp, or with the PA amp(s)? Fixable? Is it something that happens with all amps?

 

So many questions... this just weirds me out.

[Jamesg]

Dude... this has killed people on stage!

 

Your amp is plugged into a different circuit than the vocal pa, and power is shorting to ground through you... Plug your amp into the same outlet as the vocal amp and it should be ok...

 

I'm not sure if this also means that there is a problem with the earthing or a short on either amp. I'd get it shecked out just to be safe. I'd also question if it's a good idea to lift the earth on your amp. Earth is there for a reason, and there are VERY high voltages in your amp. Maybe get a power conditioner?

[VanR]

Go wireless.

[Prages]

 

Dude... this has killed people on stage! Your amp is plugged into a different circuit than the vocal pa, and power is shorting to ground through you... Plug your amp into the same outlet as the vocal amp and it should be ok... I'm not sure if this also means that there is a problem with the earthing or a short on either amp. I'd get it shecked out just to be safe. I'd also question if it's a good idea to lift the earth on your amp. Earth is there for a reason, and there are VERY high voltages in your amp. Maybe get a power conditioner?

 

 

 

I was going to suggest this. It doesn't have to be the same outlet, but your guitar amp should be plugged into the same circuit as the PA.

[RaVenCAD]

Sounds to me like the outlet isn't grounded properly. Have it checked. Is it an old house? A lot of older homes have little to no grounding on the outlets, it's insane. When I bought my house, my home inspector found that none of mine were grounded. In my state, that's a huge code violation. The previous home owner had to bring the wiring up to code for me or else my inspector would have had the structure condemned. They even ate the cost of it, because they legally had no choice if they wanted to sell it. Not being a total jerk, I agreed to split the cost of a slightly bigger upgrade (new circuit breaker, new wire and new outlets all over the house) instead of them eating the entire thing. But yeah, I agree, that's a MAJOR safety hazzard.

[BootRoots]

 

Go wireless.

 

 

bingo. I use my wireless all the time for gigs. you never know what kind of shoddy wiring a club might have.

[telemanjam]

 

I believe what's happening is that your guitar amp is not grounded well, and when you touch the guitar and the mic, YOU're grounding the amp to the PA. Check the plug/grounding on your amp.

 

 

Or the mic/PA isn't grounded well.

 

Or it's the wiring in the building.

 

 

In reality, the amp itself is probably the last source of the problem.

 

 

My bet would be on poor wiring in the building.

[datru]

You can check the wiring of any outlet with a cheap device that looks like this:

 

 

It has three LED's and will let you know if the ground is disconnected or swapped with the hot or common. Really cheap way to be sure.

[JSRocker]

Not to judge a book by it's cover but...

 

 

Yeah... It's a nice place, but it's pretty shoddy.

 

I doubt that the wiring is good.

 

But it very well could be the amp. What are the odds of the wiring being bad at this place, our manger's house, and my church? We used a different system each place.

[JSRocker]

 

You can check the wiring of any outlet with a cheap device that looks like this: It has three LED's and will let you know if the ground is disconnected or swapped with the hot or common. Really cheap way to be sure.

 

 

Where can you get one of those?

[peavey_impact]

I'd say its a ground problem with your PA, not your guitar amp.

[JSRocker]

 

I'd say its a ground problem with your PA, not your guitar amp.

 

 

We've used a different PA at all three places.

[datru]

 

Where can you get one of those?

 

 

They are readily available at any hardware store. I think they are called outlet checkers or circuit analyzers. Describe it, they'll know.

[peavey_impact]

 

We've used a different PA at all three places.

 

 

try touching something metal besides your guitar and touching a mic at the same time. thatll tell you if its the PA. In my old jamspace our PA always did this; if you touched your guitar strings and the mic - ZAP!

 

If you touched anything else metal and the mic - still a ZAP!

[mc5nrg]

What kind of amp?Does it have a 3 prong grounded power cable or is it an older amp with a two prong plug and polarity switch? Reverse the polarity switch if that is the case.Test the mike with the back of your hand .

 

Its possible there is some sort of electrical problem in the amp if it is a modern amp with the grounded plug or if converted it wasn't done properly.

[Puddlegum]

Yeah, your amp or outlet isn't grounded properly. You should get that fixed ASAP.

 

Funny story, Ace Frehley was once knocked 30 feet from the stage because the his amp wasn't properly grounded on the stage. It knocked him out cold.

 

I remember seeing that also happen to my bass player in high school. He had an old Gibson Bass rig that wasn't grounded right. The first time he got close to the mic, you could see the sparks shooting.

[Frets99]

[dcindc]

guitarnuts.com

 

Install that blocking capacitor mod. You are asking for it.

 

Good luck!

[Roy]

You have a bad electrical ground. Wireless won't fix the problem, only hide it. Do not lift the ground on your amp, it's there for safety. What is happening is that there is a 110V charge looking for a path to ground and not finding it electrically. It sees you as a 10 foot copper rod sunk into the ground. Don't buy one of those LED testers, it may not give you the whole story. I have one and used it to test the ground on at outlet. Seemed okay. Did you know that if you plug a marshall into an ungrounded outlet, it'll eventually build up a charge and send 110V into your guitar strings? I do. I tested the outlet with my voltmeter and the ground was present but weak, about a 50v circuit. Fix the problem at the source and do it properly. Try to plug into the same circuit as the P.A.

[JSRocker]

 

What is happening is that there is a 110V charge looking for a path to ground and not finding it electrically. It sees you as a 10 foot copper rod sunk into the ground. Don't buy one of those LED testers, it may not give you the whole story. I have one and used it to test the ground on at outlet. Seemed okay. Did you know that if you plug a marshall into an ungrounded outlet, it'll eventually build up a charge and send 110V into your guitar strings? I do. I tested the outlet with my voltmeter and the ground was present but weak, about a 50v circuit. Fix the problem at the source and do it properly. Try to plug into the same circuit as the P.A.

 

 

That sounds nasty. By the way guys... my bandmates may be stopping by to check up on the problem. We are all Christians, so I would appreciate it if you didn't curse in your postings. Thanks.

[angus_old]