My guitar tried to kill me last night

[buckaroobanzai]

Well, not really, but my lips still hurt...(insert nudge nudge wink wink joke here)

I hadn't experienced mic shock before, it's not fun. We were playing at the rehearsal studio, me using my recently upgraded SX LP clone into a new Crate V18 amp. I was using a non-boom mic stand and happened to bang the guitar strings against it while singing. Ow. Not enough to put me on the floor, but the song sure went to hell at that point.

Some investigation found the following:

Room is properly grounded (checked with tester)
Amp is properly grounded ( and is almost brand new)
Cables are good ( 1 cable, straight into amp)
Guitar ground wire to bridge is good but there's some small hum when I'm not touching the strings ( the guitar was like this before I swapped out the pots and pickups as well)
I had a voltmeter in the car, and it measured 14v AC differential between the guitar and the mic when the guitar was not in contact with the mic stand, and it jumped to 46v AC when I grounded the strings against the mic stand.
I also play bass, and there was no voltage registered when trying this with the bass (different amp obviously) The only thing I should have tried in hindsight was borrowing another guitar and seeing if the same thing happened. I'm wondering if my guitar upgrade ( my first one) went bad somehow - I installed GFS pickups and CTS pots with all new wiring, following the standard LP wiring diagram that ships with the GFS pickups. What should I check on the guitar to see if I screwed the wiring up?

[Milkman]

Well, not really, but my lips still hurt...(insert nudge nudge wink wink joke here)

I hadn't experienced mic shock before, it's not fun. We were playing at the rehearsal studio, me using my recently upgraded SX LP clone into a new Crate V18 amp. I was using a non-boom mic stand and happened to bang the guitar strings against it while singing. Ow. Not enough to put me on the floor, but the song sure went to hell at that point.

Some investigation found the following:

Room is properly grounded (checked with tester)
Amp is properly grounded ( and is almost brand new)
Cables are good ( 1 cable, straight into amp)
Guitar ground wire to bridge is good but there's some small hum when I'm not touching the strings ( the guitar was like this before I swapped out the pots and pickups as well)
I had a voltmeter in the car, and it measured 14v AC differential between the guitar and the mic when the guitar was not in contact with the mic stand, and it jumped to 46v AC when I grounded the strings against the mic stand.
I also play bass, and there was no voltage registered when trying this with the bass (different amp obviously) The only thing I should have tried in hindsight was borrowing another guitar and seeing if the same thing happened. I'm wondering if my guitar upgrade ( my first one) went bad somehow - I installed GFS pickups and CTS pots with all new wiring, following the standard LP wiring diagram that ships with the GFS pickups. What should I check on the guitar to see if I screwed the wiring up?

If you play long enough you're likely to get blasted more than once.

I've had several shocks that could have killed me.

I have two solutions and I use both.

1. Wireless. problem solved

2. EMG pickups (internally grounded so no wire running to the bridge). Again, problem solved.


Yup, shocks are no fun at all.

[Supro]

GuitarNuts.com has a wiring post on how to put a high voltage cap in the guitar to avoid just that.....actually they have a very good wireing scheme using star grounding for single pole pickups as in strats. I did that wireing and set up the cap, my strat is dead quiet now, even in neon infested places....I don't use a tube amp so I never got shocked, but still the cap is in there to prevent this.

[Geek]

Even in gear with perfectly functioning grounds and safeties, induced EMF can be nasty.
(spent MONTHS chasing a ground hum problem only to find moving an electrical wire over 2M cured it :rolleyes: )

[Hamm Guitars]

Every time you run into a situation where you have a guitar and a microphone that you will be singing into, do the following and it will at least save you from being knocked on you ass:

1. Set up your gear and power up.
2. Make sure that the PA is on.
3. Hold your guitar by the wood and touch the strings to the mic.

If there are sparks, it's not safe. Mic condoms are not a solution to the problem - they will get at least a little wet and then they will conduct. Find the source of the problem and fix it - it should not involve lifting AC grounds.

I've seen a few guys take a belt of electricity over the years, it's not a pretty sight.

[Paul]

I always:

Use one of those $5.00 outlet checkers to make sure the outlets are wired properly.

Check the voltage on the outlet with a "wiggy".

http://www.squared.com/us/products/machine_safety.nsf/unid/58870E11543C976885256D500050927B/$file/wiggy.htm

Use a GFCI protection for anything plugged in.

Use the aforementioned wiggy to test for voltage between guitar and mic.

By "always", I mean every time I plug in somewhere other than my own home. Every Sunday night at rehearsal I ALWAYS check the outlets first.

I don't get shocks anymore.

Last Sunday I played at an informal jam for two songs. I didn't have an opportunity to test anything, and I made damn sure I didn't touch anyone. That was a rare exception for me. I was somewhat uncomfortable not knowing for absolute sure about the level of electrical safety.

[mrmatt1972]

Use the aforementioned wiggy to test for voltage between guitar and mic.


For the technologically inept, can you explain the process here? I use an outlet tester and a power bar with a circuit breaker, and I could do the spark thing, but I'd rather not!!

matt

[Ripper]

just out of curiousity you're not on a bare concrete floor are you?

[fraser]

when i used a pair of ampeg reverbojets regularly, i got shocked every night.
since i was a kid, ive been zapped countless times. till only a few years ago i thought it was just normal:smile:

[Robert1950]

Not to take away from the seriousness of this thread, every time I see it, Frank Zappa's "My guitar wants to kill your mama" starts playing in my head.

[buckaroobanzai]

when i used a pair of ampeg reverbojets regularly, i got shocked every night.
since i was a kid, ive been zapped countless times. till only a few years ago i thought it was just normal:smile:

We're musicians. Normal is a fluid concept.

[zontar]

I remember finding out about this stuff when I was taking lessons and we had bands. The teacher warned us about it, but we had to try it out for ourselves. :smile: Of course other times we forgot. Then when I taught and had bands--the students had to try it for themselves as well. The worst is when it goes through you from arm to arm--that goes through your heart--not pleasant at all. I once had a welt on my hand from forgetting this & moving a mic stand.

just out of curiousity you're not on a bare concrete floor are you?

I used to experience that when I was growing up & we had a part of our basement as open space. When people came over to jam I'd tell them to leave their shoes on. I found out about it the hard way. Fortunately it was only a slight buzzing.

[Paul]

For the technologically inept, can you explain the process here? I use an outlet tester and a power bar with a circuit breaker, and I could do the spark thing, but I'd rather not!!

matt

The "Wiggy" is a passive device, batteries not required. When everything is connected and on, PA, amp, guitar plugged in, etc. touch one lead of the wiggy to your guitar strings, or the output jack plate, something metal that you know is connected to "ground" on your guitar.

Touch the other lead on the wiggy to the metal grill of the mic, or the metal part of the mic cable, or the little screw that holds the mic connector together, again, something that you know should be ground. If the wiggy lights up and the gage shows voltage, that's bad, and you should fix the problem. Check several times at several places.

I use the outlet checker and the wiggy, (a multimeter can be used as well), because they don't need a battery. They always just work.

Milkman's use of wireless avoids most of the consequences of the problem, but does not fix the problem.

[elindso]

The dreaded Blue Flame.

I've an old Traynor GuitarMate amp that will shop you if you touch something else while playing.

[Gear Pig]

We put together a benefit for a friend of ours a few years back and ended up having a faulty ground in a brand new extension, I got hit a couple times getting to close to the mic, the last one I took though was really bad and stunned me, our frontman looked at me and asked why I wasn't pulling the lead break and realized I wasn't to sure where I was!! The worst part was the cable didn't fully fail until before we got up, 4th group in, so we had no warning! It definitely isn't a fun experience!!

[DeleriumTrigger]

This is scary since I haven't been shocked yet but I recently started singing while playing with a mic/mic stand.

I have active EMG pickups in my guitar, will this internal grounding totally protect me or should I still be taking precautions?

:rockon:

[Hamm Guitars]

If your bridge is grounded to your jack, all it takes is a lifted ground and a reversed hot and nuetral at the AC plug and you'll get a leathal shock.

Some might sa that this is unlikely, but I've seen alot of recepticles in clubs that were wired backwards, and lots of techs that will lift AC ground to fix a buzz....

[dwagar]

The "Wiggy" is a passive device, batteries not required. When everything is connected and on, PA, amp, guitar plugged in, etc. touch one lead of the wiggy to your guitar strings, or the output jack plate, something metal that you know is connected to "ground" on your guitar.

Touch the other lead on the wiggy to the metal grill of the mic, or the metal part of the mic cable, or the little screw that holds the mic connector together, again, something that you know should be ground. If the wiggy lights up and the gage shows voltage, that's bad, and you should fix the problem. Check several times at several places.

I use the outlet checker and the wiggy, (a multimeter can be used as well), because they don't need a battery. They always just work.

Milkman's use of wireless avoids most of the consequences of the problem, but does not fix the problem.

what kind of voltage are you concerned with using a Multimeter?

[Paul]

what kind of voltage are you concerned with using a Multimeter?

Any voltage is a problem. There should be, must be, no voltage. That's why I always check. I have no idea if somebody replaced an outlet since the last time I was there.

Milkman tends to bring his own AC distro, so he ties into the panel. Any problem with a lifted ground, or switched hot/neutral would be his own doing at the point he tied into the panel.

I usually have just a small powered PA mixer and my guitar amp.....usually plugged into the same source. It is just a matter of habit for me to check before playing.

[Wheeman]

Any voltage is a problem. There should be, must be, no voltage. That's why I always check. I have no idea if somebody replaced an outlet since the last time I was there.

Even 4.5V DC from a USB cable is too much. I was unplugging my MP3 player from the USB cable charging it, while my arm was touching the strings of my guitar. Zap! Who ever designed the USB-Mini Male format I want to kick in the shins hard. Luckily the arm was the same arm that touched the cable.

Normally, I would consider what you do almost paranoid, but I guess it only takes once (or seeing somebody else) to make you so. Electricity is scary stuff regardless.

My physics teacher once pulled out a transformer that outputs millions of volts. He let those with the balls to touch the electrodes with the side of our arms. Even the touch of one electrode hurt. As long as we didn't grab the electrodes with both hands we were fine.

[bscott]

With a handle like yours, are you sure it's not a being from another dimension - or world, who is trying to break through to "our" side. OR perhaps a worker from the "Growing, Excited" corporation that is really a front for extraterrstials??!

Brian

[buckaroobanzai]

With a handle like yours, are you sure it's not a being from another dimension - or world, who is trying to break through to "our" side. OR perhaps a worker from the "Growing, Excited" corporation that is really a front for extraterrstials??!

Brian

Well, the zap did allow me to see the evil black Lectroids that have infiltrated our society.

- or perhaps they were just the black-metal band that was rehearsing next door....

[Milkman]

Well, the zap did allow me to see the evil black Lectroids that have infiltrated our society.

- or perhaps they were just the black-metal band that was rehearsing next door....

Let me guess. You had a roll of cookie dough in your pocket (not just glad to see me) and they came out fully cooked.:eek:

[natelp]

My APC surge suppressor has the 'building wiring fault' light on. There is some hard-to-trace buzz going on but since this is just at home for goofing around right now I haven't been too concerned, until I read this thread.

I live in an apartment building, so I have basically no control over its wiring. I plugged it into every outlet in my apartment and the light comes on. Any ideas on how to figure out what is wrong with the wiring, and what to do about it?

[buckaroobanzai]

Let me guess. You had a roll of cookie dough in your pocket (not just glad to see me) and they came out fully cooked.:eek:

The chocolate chips melted.

Didn't do the nuts much good either.

[Hamm Guitars]

Go to Canadian Tire and get an outlet checker (about 6 bucks). It plugs into the outlet and it has three lights on it. The lights come on and you look at the colour code and it tells you what is wrong. It is possible that your surge protector is goofy and the wiring is O.K.

If the tester shows a fault, then call the super and have it fixed. If it is all of your outlets, either a really consistently bad electrician installed all of your outlets, or the mains wires are reversed at the fusebox.

You building super has to fix this, otherwise they would be liable if anything should happen.

My APC surge suppressor has the 'building wiring fault' light on. There is some hard-to-trace buzz going on but since this is just at home for goofing around right now I haven't been too concerned, until I read this thread.

I live in an apartment building, so I have basically no control over its wiring. I plugged it into every outlet in my apartment and the light comes on. Any ideas on how to figure out what is wrong with the wiring, and what to do about it?

[zontar]

Go to Canadian Tire and get an outlet checker (about 6 bucks). It plugs into the outlet and it has three lights on it. The lights come on and you look at the colour code and it tells you what is wrong. It is possible that your surge protector is goofy and the wiring is O.K.

If the tester shows a fault, then call the super and have it fixed. If it is all of your outlets, either a really consistently bad electrician installed all of your outlets, or the mains wires are reversed at the fusebox.

You building super has to fix this, otherwise they would be liable if anything should happen.

And hopefully you have a good landlord. I know people who bought homes and had to re-do all the wiring because the whole house was done incorrectly. What's scary is I played electric guitar in one of them several times--BEFORE the wiring was redone.