Charles.Doughty
30 posts
Jan 14, 2014
4:12 AM
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Ok so I am tired of getting zapped on the lips when I step up to my vocal mic.
Here is the scenario: I am holding my harp mic. My amp is grounded and has a three prong chord. My lips are wet from playing harp and I step up to my old Shure 55 vocal mic and Zap! My lips and my nose are now numb and I am rattled because it has happened again. How do I fix this?
The 55 has a three prong connector but it is not xlr. If I change it to an xlr will it fix the problem?
Please help.
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5F6H
1733 posts
Jan 14, 2014
4:21 AM
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What is the 55 connected to and have you checked that device has a 3 prong cord and that any AC extension blocks also have an AC ground?
You can check continuity of the mic cable (female 1 to male 1, female 2 to male 2 & so on) with a DMM if it makes you happy, it's more like the problem relates to wall AC grounding though.
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jbone
1462 posts
Jan 14, 2014
4:21 AM
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Try a process of elimination. Beg steal or borrow an sm58 and cable and use it instead, and see if that happens. I'm no electronics wiz but it does sound like a poor ground.
Another possibility to look at is, what is the building's ground setup? If it's older it may not be a good ground and I've run into that a couple places as well.
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dougharps
515 posts
Jan 14, 2014
8:16 AM
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Twice I have played in settings that provided extension cords that I later discovered had the grounded plug prong cut off at the wall end of the extension cord. One was outdoors in a tent after a rainstorm, the other had a cement floor. We discovered it by getting zapped.
This is a cheap solution to check your ground, available at any hardware store and Amazon, etc:
Electrical outlet tester
At both venues I spoke with management after discovering this. At the tent they got us a new cord. At the venue with the cement floor 2 months later it was unchanged, so I used my own cord that I brought with me to the gig.
At other venues I have found sometimes that the outlets themselves are wired improperly. You should use another outlet that is properly wired, if possible.
Finally, to minimize risk you can try to run your amp off the same circuit as the PA your mic is in, so you avoid the possibility of doubling the voltage difference if the circuits are out of phase.
Trying a different cord and a 58 is worth trying as a step in trouble shooting, but I think the problem goes beyond the mic to the PA or amp, the extensions, or house circuits.
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Doug S.
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Greg Heumann
2559 posts
Jan 14, 2014
9:09 AM
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It is unlikely a poor electrical connection to ground. You either have a connection or you don't. If the mic works and you're NOT using XLR then the ground is intact between the mic and the PA.
It might not be the 55/PA's fault. It could be your harp mic/amp combination. If they are not grounded, OR plugged into a different circuit at the venue (which can have a different ground potential) that's all it takes.
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***************************************************
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BlowsMeAway Productions
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Last Edited by Greg Heumann on Jan 14, 2014 9:11 AM
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dougharps
516 posts
Jan 14, 2014
10:35 AM
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Greg has a good point about different ground potentials if the venue isn't properly grounded. If the circuit is running heavy equipment that could cause other issues with power to amp and PA.
But the issue that just came to mind is your mention of the 55 not having an XLR connector, but a different 3 prong connector. How are you running this to the PA (what cable?) Could the wiring between the PA and mic connector be incorrect? Is the phantom power turned on on the PA?
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Doug S.
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MP
3054 posts
Jan 14, 2014
12:08 PM
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Every now and then I play a room that is not properly grounded. I HATE GETTING SHOCKED! It is always the way Charles describes it.
I keep one of those foam wind screens to put over my SM-58 vocal mic and that solves the problem as a quick fix. You may have to readjust your settings on the vocal mic though. Since I sing all the tunes I never gig w/out that wind screen.
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barbequebob
2443 posts
Jan 14, 2014
12:40 PM
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Venues that have old and really funky wiring can be a constant problem with ground and there's been plenty of times I've used my real '59 Bassman an have gotten shocks like crazy and often had to turn the polarity switch to a different position several times during a gig. I also had such a problem when I did a gig at an old amusement park that had a similar problem as well.
The non XLR connector sounds like real old school stuff and if it has that, these were originally hi-z mics.
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Charles.Doughty
31 posts
Jan 14, 2014
3:59 PM
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Thanks for the info. Man it's really buzz kill when I get shocked in the lips and nose, depending which one gets to the vocal mic first.
The 3 pin connector looks like xlr and it fits into the xlr jacks on the pa but I believe they are an older pre-xlr configuration.
@Greg, my harp amp is a Kalamazoo II that I got from you, so I'm pretty sure that's not the problem.
There are some pops every once in awhile from the pa so I'm pretty sure some old 1920s wiring is in older at our practice space.
Here is a guaranteed way for me to get a good poke. Holding my harp mic and touching my 66 Ampeg bass amp with the original 2 pronger. Holy man! Just thinking about and I get a metallic taste in my mouth.
Thanks for the help everybody.
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Jehosaphat
652 posts
Jan 14, 2014
4:21 PM
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This is only happening in your practice room?
Don't mess around,get an electrician in to check out the wiring system.
A few dollars is not worth your life.
A zap yesterday could be a deathbolt tomorrow.
Seen it happen.
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Gp
3 posts
Jan 14, 2014
4:58 PM
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At the local jam last Friday night the bass player was getting a mild zap from the mic which was plugged into the PA. The host fixed it by plugging the amp from the top outlet to the bottom outlet of a double outlet. One would think that both outlets would have been grounded. Good advice to keep a tester in the gear bag, never know what you find from place to place or outlet to outlet.
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12gagedan
295 posts
Jan 14, 2014
7:59 PM
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It's also good to carry a GFCI plug. I use one when outside/rainy or when a place is old/sketchy.
Funny story; I got shocked at rehearsal last week, switched the ground and then got REALLY shocked. The first one was just static electricity.
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Last Edited by 12gagedan on Jan 14, 2014 7:59 PM
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Greg Heumann
2561 posts
Jan 14, 2014
8:40 PM
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Yeah your Zoo is not the problem - I can assure you it is properly grounded. However that doesn't mean it isn't participating in the circuit that shocks you. It provides a path to ground all the way through the mic cable shield to the mic metal itself. The OTHER mic should ALSO be connected to ground through ITS cable shield, which should be grounded through the amp/PA to which it is connected. You get a shock when those two "grounds" aren't in fact at the same electrical potential. Again - the most likely culprit is different outlets having different ground potential and if this is at your house you should have an electrician check it. If it is at a club where you play, try plugging the amp into the same 100V circuit that the PA (or whatever amp your vocal mic) is plugged into.
If that does NOT solve it then there is indeed a serious problem in the connection between the PA's ground where its plugged in, up to the jack where your cable is plugged in, all the way to your mic. That should ALL BE GROUNDED.
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***************************************************
/Greg
BlowsMeAway Productions
See my Customer Mics album on Facebook
BlueState - my band
Bluestate on iTunes
Last Edited by Greg Heumann on Jan 14, 2014 8:41 PM
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