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Here's another one for ya. Just a week or so ago, I had two gigs in a row; one that ended at 9:00 pm and another that started at 9:30 pm. I tore down the small PA at gig one, hopped in a taxi (car wouldn't have worked because parking would have taken too long) and got to the other gig at 9:20 pm. I had a second PA there already fired up and ready to go (one speaker, one sub) and just needed to rush to get my personal gear set up. Plugged in my pedals, grabbed my guitar, tested the mic and blam!!! A huge shock that was really... well, shocking. In my haste, I had plugged in my guitar pedal adaptor into just the one side of an AC cable. I doubt if I'll do that again.

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We had our poor bass player getting shocks through guitar and mic. Checked wiring and found two faulty extension cables. Plugs looked good must of been inside Cable somewhere.

It might be a silly question, but why is your bass player equipped with a (vocal) mic?

 

I've rarely heard of such a thing. Don't tell me he has a wedge monitor too? And a pedal board? And a bunch of groupies? And doesn't own all of the PA and lighting rig, and isn't the tech for the band that could otherwise figure this problem out?

 

weirdness here... something ain't right at-all.

 

To clarify: This is a bass player we're talking about... 4 string bass right? Left brain sort of person? What kind of pick-up, van, or box truck does he own? He does have a wife with a good job down at the county court house... right??? He built the extension cables, right???!!!

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Not sure what's all that's about. He is a pro bass player who sings a few songs and kinda fronts the band with the banter ect. We have a mains tester and should have used it first but that's life. He can play 4/5 and bouble bass, so not a hairbrain as you suggest.what a strange reply.

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We had our poor bass player getting shocks through guitar and mic. Checked wiring and found two faulty extension cables. Plugs looked good must of been inside Cable somewhere.

 

Are you absolutely positively certain that was the problem? I'm not.

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It might be a silly question, but why is your bass player equipped with a (vocal) mic?

 

I've rarely heard of such a thing. Don't tell me he has a wedge monitor too? And a pedal board? And a bunch of groupies? And doesn't own all of the PA and lighting rig, and isn't the tech for the band that could otherwise figure this problem out?

 

weirdness here... something ain't right at-all.

 

To clarify: This is a bass player we're talking about... 4 string bass right? Left brain sort of person? What kind of pick-up, van, or box truck does he own? He does have a wife with a good job down at the county court house... right??? He built the extension cables, right???!!!

Yes it is a silly question of course he has a monitor and a mic.

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Yes it is a silly question of course he has a monitor and a mic.

I apologize that I got your panties all bunched up.

 

It was somewhat of an inside witticism in that:

 

1) I'm a non singing bass player who owns the PA and lighting rig our band uses... as I have for going on 4 decades.

 

2) I'll suggest that the preponderance of sound tech band PA gear folks are seemingly bass players.

 

3) Seemingly few bass players sing or otherwise have a need for a vocal mic.

 

ok... well... back to serious business.

 

I believe Don (dboomer) opened the door to discuss the possibility that the shock problem is otherwise likely not related to the cable part of the extension cords... I tend to agree.

 

So what are you running for extension power cabling as well as the rest of the PA rig?

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Well we replaced the extension leads and all was ok. He was the only one effected, the guitarist was ok just his electric feed.our mains tested confirmed an earth fault.
I'm not sure that actually proves what you think it does. You might be right but you also might be betting someone's life on it.
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Yes it is a silly question of course he has a monitor and a mic.

 

Maybe humour is in the eye of the beholder. I thought Mark's reply was hilarious - as long as you realize he's poking fun of his brethren, and is doing so in a good natured way. I'm a guitar player, so I've heard all the guitar player lightbulb jokes - how many guitar players does it take to screw in a lightbulb? One, and nine to say they could have done it better... Drummer jokes are in abundance as well. How can you tell it's a drummer knocking at the door (I'm not even going to finish that one).

 

Anyway, I wasn't suggesting it was the bass player's pedals, just relating something that happened to me.

 

However, IMHO you should listen to dBoomer, and make sure it wasn't just the extension cable. Don doesn't just say things to hear himself type, so maybe digging deeper would be a worthwhile thing to do. Check out the general power you're using, the bass player's amp, and so on.

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The venue power outlet/socket was ok tested. We had multiple extensions as outlets were few and far between. Bass amp mesa 400+ plug was wired ok no reason to think anything else. No pedals used. No hums or buzzing.

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I was bass player soundman in the last band I was in too. You know I find it difficult to play bass lines and sing at the same time kind of like patting your head and rubbing your belly at the same time. If I play guitar I can sing no problem. I saw an interview once with Glen Campbell and he use to play with the Beach Boys for a period of time and he said the hardest thing he ever did was play bass and sing harmonies. Some people seem to be able to play bass and sing no problem?

 

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I was bass player soundman in the last band I was in too. You know I find it difficult to play bass lines and sing at the same time kind of like patting your head and rubbing your belly at the same time.
I hate it when the bass skips the iconic riffs in a song - but IME nailing it note-for-note gets you ignored vs faking your way through it and doing good harmonies or singing lead, even in the ears of your bandmates who IME are usually tone deaf below the guitar low "E" <facepalm>.
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The venue power outlet/socket was ok tested. We had multiple extensions as outlets were few and far between. Bass amp mesa 400+ plug was wired ok no reason to think anything else. No pedals used. No hums or buzzing.
I'm very limited in what I can post because someone might take that as a position from my company ( which it is not ). So I have to avoid commenting much about AC supply and things like flying speakers. But ask yourself ... What causes someone to be shocked? The answer is they are getting voltage to their body and then there is some path for the voltage to ground causing a current flow in your body. So how could that have happened with a faulty extension cable? Were these cables handmade? I don't know the answer without actually being there and testing. Much more likely that one of your amps is allowing voltage to get to where it shouldn't be. Heres an instance where you should hire some professional help. Someone's life could depend on it.
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I agree completely with Don. You really need to find the source of the problem. The fact that you haven't found the problem doesn't mean it no longer exists. If you aren't really well trained in electrical systems, get a professional who's qualified to do the troubleshooting. I've seen people get seriously injured (burns, permanent nerve and muscle damage....no more playing bass or guitar) by these types of shocks.

 

If the bassist got shocked when he touched the mic and the bass strings simultaneously, this indicates a fault with current passing from a mains hot wire and the chassis of the bass amp or the PA gear which should be at ground potential. It also means there may be two problems:

 

1. There's a fault to ground (chassis) somewhere in the rig.

2. There was *possibly* no grounding from the fault to the house mains ground. A small fault may not trip a breaker yet deliver a helluva shock. But it's still very important to check all power cables, cords and extensions for ground continuity when this sort of problem crops up.

 

 

1/4" (TS or TRS) plugs and jacks often have the sleeve contact connected to the chassis of the device (amp, mixer, pedal, etc.). The mains power ground wire is also typically attached there. So this means that the case of a microphone is electrically at the same potential as the house mains ground. If voltage is applied to a mic case via a fault, it should pass to ground. If the power is provided through a GFCI, such a voltage (fault) should trip the GFCI. It may not be enough current to trip the house circuit breaker or open the fuse. Obviously if there's no ground back to the house mains, the breaker will absolutely NOT trip with a fault to ground. A GFCI will still work perfectly without any grounding system at all.

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Thanx for the advice, when we replaced the faulty cable everything was ok. No other member had the problem. Cables were not hand made. Can't see if they were what difference it would make. They were old I admit and used most weeks.

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Thanx for the advice, when we replaced the faulty cable everything was ok. No other member had the problem. Cables were not hand made. Can't see if they were what difference it would make. They were old I admit and used most weeks.

 

What was faulty in the replaced extension cord?

 

My concern here is that an extension cord that, for instance, has a broken ground prong, will only be a problem if there's another fault in the equipment it powers. A missing ground in and of itself will not result in someone getting shocked, it only prevents a fault from being cleared. The ground conductor doesn't pass any current in normal operation.

 

To illustrate by example, If the Mesa amp had an internal wire come loose and that wire touched the amp chassis (case), the case and the 1/4" guitar cables plugged in would become energized at whatever voltage was on that wire. If the grounding is complete and unbroken in the amp, the power cable, and the house wiring, the voltage on the chassis/plug/cables would complete a short circuit to the breaker panel, tripping the circuit breaker. If the grounding is broken, say by using a "cheater" adapter plug, or by broken ground wires in the extension cord, that fault current can't complete the circuit back to the breaker panel. But the bassist who is touching the bass strings and then touches the mic (which is attached to the PA that IS grounded correctly) acts as a pretty good conductor of electricity, and he completes the circuit to ground, getting zapped in the process.

 

This is why using GFCI's on anything people come in contact with is a good idea. They will trip with only a tiny (5 milliamps) current leakage.

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I know this doesn't solve anyone's faulty wiring problems or ground lift issues, but when I use my Sure wireless system with my guitar I don't even think about shocks.

 

This is true if you are wireless for both the mic and the guitar. If either is hardwired back to the amp or PA, you can still potentially be shocked if your body is touching another grounded object.

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If the bass amp was faulty.why did the problem go away with a replaced mains extension. Thanx for the tips and advice I k ow a good electronics man will bendhisear on this aswell. He,s hoping to be in the us soon in LA Rick Rubin is producing an album with one of the bands he plays with.

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If the bass amp was faulty.why did the problem go away with a replaced mains extension. Thanx for the tips and advice I k ow a good electronics man will bendhisear on this aswell. He,s hoping to be in the us soon in LA Rick Rubin is producing an album with one of the bands he plays with.

 

Again, what was wrong with the extension cord? It's difficult to know for certain what the problem(s) are, with the info we have in this thread. I don't know and didn't say whether the amp is faulty, I stated an example of how it often takes more than one defective part to cause a shock. It is extremely important to read and understand the details in a topic like this.

 

However I can give one possible scenario where both the amp and the cord are defective, and replacing the cord will stop the shock....but not stop the danger or problems in the amp. If the amp has a small leakage of current to ground, there can be enough current to cause a painful shock. If the cord with the defective ground is replaced, the working cord's ground conductor will clear the fault but not trip the breaker because the leakage current, though plenty to hurt a human, isn't enough to trip a breaker. Again, a GFCI would trip because its threshold is three thousand times more sensitive than a circuit breaker. (5 milliamps versus 15 amps). So the cord replacement makes you think all is well, but in reality the amp is still dangerous. Merely touching the amp chassis and a grounded object can still cause a shock.

 

Check the extension cord with an ohmmeter, WITH THE CORD UNPLUGGED. Each prong should connect to the corresponding socket...there's a thin blade and a wide blade, and the round ground pin. There should be zero ohms read from the thin blade to the thin socket. The same for each conductor. There should be infinite resistance between any socket to any other socket. If you read very low resistance between any two conductors, there's a short. If any plug has high resistance or infinite resistance to its corresponding socket, there's a break in that wire. It's also possible that either the socket is worn or loose enough to make intermittent contact to something plugged in to it, or that there's an intermittent break in one or more of the wires. So it may test okay until it's moved again.

 

If you have access to a good electrician, ask him to "megger" the cord. This is a test of the insulation and wiring with a device called a megohm meter, that applies a high voltage to the wire and reads the amount of leakage to the other wires in the cord. It will positively identify bad insulation caused by too much bending or walking on a cord.

 

These potential issues are why it's important to regularly check your cables and cords, and to give them care in use and storage. Gear used in public places is subject to all sorts of abuse that happens when you aren't watching.

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Hey, that was a great explanation, Craig. I've been trying to think of a scenario that would explain his observations, and that one is a great candidate, which would have never crossed my mind.

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Great advise,the extensions cables are now history and replaced with new,so on to checking out amps etc.many thanx for those who helped very-happy.png.197c47f720636f02390cc2b0a33804da.png' alt='smiley-veryhappy'>

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