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Sm 58 shock troubleshoot

L

Low_Ryder

Feb 13, 2012
155
8
Michigan
#1
I am attempting to learn to sing and play at the same time, and the dang mic shocked my face!


What is going on? I've seen several posts and web pages about it, and it seems to have something to do with bad ground. Funny thing is, it only happens with the sm 58. Doesn't matter what mixer input, which mic cable, which mic stand. If I touch my strings and then the sm 58 I get a shock.

Thoughts? I saw something about testing with a multimeter but when I tried my numbers were different than what the articles described. I get OL (overload?) on any combination of pins except pins 2 and 3. Then it climbed to 1.9?? and THEN read OL. Meter set on 2k. Switched to 20k and it read 9.8 something. What does that mean? Bad ground? Normal?


Thanks
 
#3
Ah, so OL means open loop. Good to know...

Is that good or bad? I really don't know much about wiring. I have tried our other mic and there are no problems with it. It's a Beta 58A. I literally swap out only the mics, and the 58 bites me no matter which line it's on, and the Beta doesn't. And if I switch around inputs on the mixer, cables, or stands (didn't think those would matter but I wanted to be thorough), it makes no difference. Beta is fine, the 58 shocks my lips. Feels like a 9v on the tongue.

Thanks again.
 
#4
I would try to find out what it is soon. People have actually died being shocked that way. It is usually due to a bad ground at the guitar amp or the power that that amp is using and, a different ground situation/circuit at the outlet the PA is using. A lot of bars have janky power, one of the reasons I use wireless. No way for me to become a ground.
 
#5
First thing to do is disconnect and check the socket outlets for live/neutral reversal and missing ground with a plug in socket tester. There is a potential difference between the guitar and mic, this is potentially very dangerous so if in any doubt have you equipment checked out ASAP.
 
#6
I appreciate all the suggestions. I have tested the two different power strips, and they both came back normal with the outlet tester. However, do you need to plug directly into the outlet to get an accurate result?
My amp and all the drummer's electronics (electric kit) are plugged into one power strip. I have 4 pedals in my line to the amp, but their power (a 1 Spot) goes to the other power strip, along with the mixer and active PA speaker.

This leads to a question we've had: How much power can draw from a single outlet without causing problems?

Any thoughts on that multimeter? How do you test a mic to see if the wiring is in proper working order?

I seek knowledge and understanding. Thanks for your patience.
 
#7
You can remove the screw on the side of the 58 and slide the 3-pin connector out to see the wiring.
No offense - but if you don't know what you are doing I'd just toss it and get another mic. If other mics are OK it certainly points to that mic being defective.
 
#8
As has been mentioned this shock condition has killed numerous musicians, even though it seems like a small shock.

Your best approach is to get the situation diagnosed and corrected by someone who knows a lot more than you do - no offense.

You're a musician, not an electrical/electronic tech.
 
#10
Low_Ryder said:
I appreciate all the suggestions. I have tested the two different power strips, and they both came back normal with the outlet tester. However, do you need to plug directly into the outlet to get an accurate result?
My amp and all the drummer's electronics (electric kit) are plugged into one power strip. I have 4 pedals in my line to the amp, but their power (a 1 Spot) goes to the other power strip, along with the mixer and active PA speaker.

This leads to a question we've had: How much power can draw from a single outlet without causing problems?

Any thoughts on that multimeter? How do you test a mic to see if the wiring is in proper working order?

I seek knowledge and understanding. Thanks for your patience.
Click to expand...
Well if you have checked your outlets, isolate from supply and now check continuity from the power lead earths (at the plug end) to the chassis of the equipment it is plugged into.
 
#11
ddnidd1 said:
As

Your best approach is to get the situation diagnosed and corrected by someone who knows a lot more than you do - no offense.
Click to expand...

No offense taken. But I still need tk know a bit more about it. For knowledge's sake, but also just to know what parts to bring in. There are 3 amps and a mixer, plus 2 guitars and 4 pedals involved in some way or another.


Silas Stingy said:
isolate from supply and now check continuity from the power lead earths (at the plug end) to the chassis of the equipment it is plugged into.
Click to expand...

Can you tell me how to do this, and what it will tell me?
 
#12
Friend what you are trying to do is analogous to a novice bass player asking how to play a particular song with an involved arrangement while he hasn't even acquired the required experience to be able to tune a bass.

You don't even understand the most basic concepts of using a multimeter, never mind basic electrical/electronic theory.

Guy, you're in over your head and dealing with something that can KILL you or someone else.
 
#14
As far as the information on this thread goes, here's how it looks:
1. Bad wiring in equipment is bad and is potentially life-threatening. I agree.
2. Get rid of your microphone. It seems to be the problem. I agree?
3. Don't get rid of your microphone. Something else is the problem. Well, what about #2?
4. This problem relates to using multiple equipment through 2 separate outlets. This sounds like something I've heard before, but what's my next step?
5. You should get your equipment checked by a professional. I sort of agree, but which equipment? Everything? That's 10 things, plus cables. And the drummer's electric kit and amp is also plugged into the same outlet, which I've mentioned, but no one can say if that is any part of the issue.

Surely there are a few simple techniques that could be adequately described to someone who doesn't even understand the most basic concepts of using a multimeter that would help to rule out certain pieces of equipment as being at fault.

I'm thinking something like this: take the multimeter and hold it to such and such part of your equipment. On a certain setting, the numbers should be in x range, meaning proper function. If not in x range, then your problem is y and it means z.
 
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#17
Joe, on the 70's I agree.

The rest of you guys weren't ejected from the womb knowing how to use a multimeter. If responding to someone without your knowledge base is aggravating to you, try another thread.

I'd like to think of TB as a safe place to ask questions. I really have no issues with a person who says. "I am seeking knowledge, help me". Got any suggestions for books or resources that *would* be helpful to the OP, please pass them along.
 
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#18
Thor, I agree. I always felt that talkBass was, among other things, a place to seek advice from more knowledgeable and experienced musicians.

Silas Stingy, that was a great video. I helped to organize some of the differnt things that I've heard about electricity an grounding. Thank you.

Still wondering how I could use a multimeter to test a mic, and also check my amp chassis for, what did he call it, voltage potential? Bad wiring essentially. Based on Stingy's earlier post, I think I unplug amp, touch one probe of multimeter to ground lug on cord, other probe to the chassis somewhere and read what it says. What I don't know is what the readout should be if it's properly grounded.


On a side note, I think I have the worst outlet tester ever. On o the lights is either slightly lit up, medium lit, or definitely lit.
 
#19
The first thing I would do is get a multimeter, set it to read AC voltage, touch one end to your guitar strings and the other end to the mic cover, to see how much voltage you're actually dealing with (Red and Black don't matter for AC).
If you don't see anything (triple check it), set the meter to DC voltage and do the same test.
After that, check the voltage between the shield of the mic cable and your guitar strings by touching one end to your guitar strings and the other to the mic cable shield.
If there is no voltage between your mic cable shield and your guitar strings, you've got a bad mic.
If there is voltage there, then this gets more complicated.

Please note that I'm not a qualified electrician, but I do understand how electricity works, and will try to help if I can.
 

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