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Post by rockstok on May 20, 2008 5:39:42 GMT -7
While playing through my Stang Ray I use SM or Beta 57 mics for vocals. I have found there is better electric shock insulation vs. SM/Beta 58 ball mics. I am getting a low level, but constant and uncomfortable shock when I touch lip to mic even with 57s. It happens in several different venues. I contacted Shure about this and they blamed it on faulty grounding in the amp. I thought they were just passing the buck but I have to ask y'all if this makes any sense?
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Post by benttop (Steve) on May 20, 2008 5:49:00 GMT -7
You'll get a shock if you've disabled the third prong on your power cord, or if the mixer your mic is plugged into has had the third prong disabled. That's called the safety ground for a reason.
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Post by rockstok on May 20, 2008 5:58:39 GMT -7
No and no. Everything is wired properly.
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Post by benttop (Steve) on May 20, 2008 7:14:24 GMT -7
Then that would indicate an issue with the house wiring. One thing you can definitely do is plug your amp into the same outlet as the mixer so that the safety ground for both are connected together. If you already have them in the same outlet and you're still getting a shock, something has malfunctioned and you should have it looked into immediately before you get a more serious shock.
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Post by Deleted on May 20, 2008 8:44:21 GMT -7
I would have to go with house wiring. I have had amps in the past that I would use and get a shock in some places and not others. I wonder if the guitar can be a culprit as well. And just to mention, although I don't know if it has any relevance, the 2 Dr Z amps that I have used, I have yet to have that problem of getting a shock from the mic. I always check by touching the mic with one hand, while the other is on my guitar. I hate surprises.
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Post by Bill on May 20, 2008 9:11:17 GMT -7
Not to add to the confusion Bill, but remember the gig we played at Federal Hill last year? I got zapped constantly during the one song I sing, and eventually had to stop playing the guitar to get through the song. I was using my Stingray that night, and I don't recall you getting shocked that night while using a Palomino.
But, I've never been zapped anywhere else using the Stingray. It's probably the house wiring, but I'd take another amp next time to that particular venue and see what happens.
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Post by telejas on May 20, 2008 9:44:32 GMT -7
No kidding, 4 out of every 5 clubs we play sets off my "Bad wiring" light on my power conditioner.
Most clubs have bad wiring and the older and more nostalgic they look, the worse the wiring.
That's just my findings around the Ozarks.
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Post by bluzman on May 20, 2008 15:28:51 GMT -7
Then that would indicate an issue with the house wiring. One thing you can definitely do is plug your amp into the same outlet as the mixer so that the safety ground for both are connected together. If you already have them in the same outlet and you're still getting a shock, something has malfunctioned and you should have it looked into immediately before you get a more serious shock. +1 what Steve sez... I even have a heavy gauge long grounded extension so I can run it from the same circuit as the PA gear to power my amp and pedals.
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Post by Hohn on May 20, 2008 19:25:49 GMT -7
Guys, a common ground is exactly what you are trying to AVOID.
When two circuits share a ground, the current has an alternate pathway to take to get to ground.
When you isolate the grounds, the only path for the current to take is back the way it came.
I'm about to embark on finishing the basement in my new house, and one feature I will be adding is isolated ground receptacles/outlets. These are a pain to add, because each outlet has it own ground running all the way back to the panel and ultimately to either the house's grounding rod (as many are grounded) or to the incoming cold water pipe (as many other houses/buildings are grounded).
As far as I can see (not far, admittedly), It's not important to have your amp plugged into the same outlet as the main board, per se. It's simply important that both the amp and the PA current have clear, uninhibited pathways to ground.
If the PA has a poor ground and the amp has a good one, then it's possible that the mic may jolt you because the current at the mic has an easier path to ground by going out through your amp.
Sharing outlets between amp and PA generally works because their respective grounds are at the same potential (same outlet, right?) But it's a false solution because the problem isn't really the lack of sharing, if that makes sense.
I might have this wrong. I've been reading up on home electrical wiring, and I might be drawing the wrong conclusions from what I've been reading. I'll see if I can dig up something definitive..
Justin
EDIT: oh, and never use a ground lift (3-prong to 2-prong adapter) on a guitar amp. It can kill you-- I'm not kidding.
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Post by Hohn on May 20, 2008 19:56:10 GMT -7
Here's what I'm talking about with the isolated ground receptacles. You've probable seen them in hospitals because many outlets in a hospital have isolated grounds to prevent damage to expensive equipment that could result if you had a similar "mic/guitar shock" scenario with expensive medical equipment.
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Post by benttop (Steve) on May 20, 2008 20:03:07 GMT -7
What you are trying to do is get to that happy place where there is no difference in potential between the guitar and the mic. Usually the easiest way to do that is plug them in to the same outlet, despite the fact that often the "correct" solution would be to properly wire all of the outlets in the entire joint. Unfortunately we don't usually have that option, so we go with the easy out.
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Post by rockstok on May 21, 2008 6:51:12 GMT -7
Just to tag on to some of the above ideas, I have been using the same grounded power strip for the guitar amp and the PA head, for better or for worse. I run a Mackie 808s from my side of the stage. Also remember that even when shocks occur, SM/Beta 57s are usually exempt due to their design.
Shure tech support blames the guitar amp. From the above posts it sounds like this is not even a possibility right?
Thanks for all the input folks.
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Post by benttop (Steve) on May 21, 2008 8:43:47 GMT -7
Just to tag on to some of the above ideas, I have been using the same grounded power strip for the guitar amp and the PA head, for better or for worse. I run a Mackie 808s from my side of the stage. Also remember that even when shocks occur, SM/Beta 57s are usually exempt due to their design. Shure tech support blames the guitar amp. From the above posts it sounds like this is not even a possibility right? Thanks for all the input folks. Oh it could be the amp - usually it would be something related to the safety ground pin on the plug though. Either it's cut off or disconnected in the amp, or it doesn't exist in the first place (like old Fender amps). Hohn is right that the ideal is for that pin to be connected directly to earth in all cases. Unfortunately, in some bars that pin is floating, or worse, connected to a voltage. In most setups, the safety ground pin on the plug is connected to your guitar strings through the amp - so you don't want voltage on there. And you don't want to be touching your strings that are grounded if your lips are touching a voltage. You want all safety grounds to be connected to earth. In some bars, you may not have that opportunity, but at least if you can get your guitar and your mic to have the same potential (voltage) then you won't get a shock. Easiest way to get that is to plug into the same outlet.
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Post by kruzty on May 21, 2008 8:59:11 GMT -7
Just to tag on to some of the above ideas, I have been using the same grounded power strip for the guitar amp and the PA head, for better or for worse. I run a Mackie 808s from my side of the stage. Does that include any power amps/powered speakers?
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Post by benttop (Steve) on May 21, 2008 10:16:40 GMT -7
Just to tag on to some of the above ideas, I have been using the same grounded power strip for the guitar amp and the PA head, for better or for worse. I run a Mackie 808s from my side of the stage. Does that include any power amps/powered speakers? The most important would be whatever you have the mic plugged into. If there are ground problems in the joint, you'll know it by the hums and buzzes in the PA.
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Post by Hohn on May 22, 2008 18:51:07 GMT -7
What you are trying to do is get to that happy place where there is no difference in potential between the guitar and the mic. Usually the easiest way to do that is plug them in to the same outlet, despite the fact that often the "correct" solution would be to properly wire all of the outlets in the entire joint. Unfortunately we don't usually have that option, so we go with the easy out. C'mon Steve-- just add it to the rider! "All outlets must have isolated grounds, be orange in color, measure exactly 124.8 Volts and have a stack of 3 Oreos next each."
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Post by drew on May 23, 2008 12:34:45 GMT -7
I've been doing gigs using new mackie powered speaker pa system and a SM58 beta mike with both the Stangray and RXJS. I've never had any shocking with the new mackie system... until last Sat night. It was a private gig at home, (nice newer multi million dollar home that was decked out to the nines). We tried running to different outlets with the same outcome. It was minimal and just got used to it. I've played my ray in some funky places with questionable power and this is the first time I've been tingled.
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Post by benttop (Steve) on May 26, 2008 17:09:21 GMT -7
C'mon Steve-- just add it to the rider! "All outlets must have isolated grounds, be orange in color, measure exactly 124.8 Volts and have a stack of 3 Oreos next each." The RIDER! Now why didn't I think of that?
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