Troubleshooting shocks

[Jersey Jack]

I'm having a bit of trouble with my set-up lately in that I'm getting shocked if I happen to touch the microphone with my lips while I have my hands on my guitar strings. I tried plugging my amplifier and pedal board into a different outlet, but that didn't work. It could be that the other outlet is on the same circuit, don't know for sure. The shocks are not extreme, but it's distraction to have to worry about touching the microphone.

 

How does one go about resolving this problem?

[soul-x]

What guitar amp are you using? Does it have a properly grounded cord?

[Axisplayer]

STOP NOW! Take the amp to a repair center. Have it checked. It is your life, but similar symptoms have lead to death. This is far too serious a topic to put off while we debate it to death on a forum.

[Craig Vecchione]

What axisplayer wrote. DO NOT use equipment that is causing a shock. Most of the time, "vintage" tube amps are the culprit if they have not been updated with a grounded power cord correctly wired. It's not an expensive upgrade, and it will save you pain, or death. I've seen some pretty horrific outcomes even if it doesn't kill.

[sibyrnes]

Here's a thread I think everyone should read:

 

http://forums.prosoundweb.com/index.php/topic,137760.0.html

[glepko]

 

STOP NOW! Take the amp to a repair center. Have it checked. It is your life, but similar symptoms have lead to death. This is far too serious a topic to put off while we debate it to death on a forum.

 

 

 

do what the man says - seriously.

[Jersey Jack]

Okay, thanks, got it. For the record, this is happening both with my Telecaster, which is runing into a new Princeton Reverb Reissue and with my banjo, which is running through a DI directly into the board, so the problem is not the amp. Perhaps a powerstrip is not properly grounded?

[Pro Sound Guy]

I'm having a bit of trouble with my set-up lately in that I'm getting shocked if I happen to touch the microphone with my lips while I have my hands on my guitar strings. I tried plugging my amplifier and pedal board into a different outlet, but that didn't work. It could be that the other outlet is on the same circuit, don't know for sure. The shocks are not extreme, but it's distraction to have to worry about touching the microphone. How does one go about resolving this problem?

Sounds to me like your guitar rig is finding ground through your sound system and YOU are the PATH to ground to the microphone. Get this issue resolved ASAP.

[W. M. Hellinger]

 

Okay, thanks, got it. For the record, this is happening both with my Telecaster, which is runing into a new Princeton Reverb Reissue and with my banjo, which is running through a DI directly into the board, so the problem is not the amp. Perhaps a powerstrip is not properly grounded?

 

When it comes to trouble-shooting, as Spock said:

 

If you eliminate the impossible, whatever remains

[nchangin]

 

Okay, thanks, got it. For the record, this is happening both with my Telecaster, which is runing into a new Princeton Reverb Reissue and with my banjo, which is running through a DI directly into the board, so the problem is not the amp. Perhaps a powerstrip is not properly grounded?

 

 

Try different circuits in different buildings? Have you taken the powerstrip out of the equation? Have you tried a different amp in the same configuration/location?

[nchangin]

Are you using phantom power on mixer by chance?

[sibyrnes]

 

Are you using phantom power on mixer by chance?

 

 

You've got to be kidding!

[Jersey Jack]

 

Are you using phantom power on mixer by chance?

 

 

Sure, I use condenser mics, so I have to use phantom power. The electric guitar doesn't go through the PA. The banjo does go to the PA, but through a DI (which requires phantom power).

[nchangin]

Isolation of components is the key in troubleshooting this. Have you removed or added any hardware recently? Try it without a condenser mic turn off phantom power see what happens?

[jwlussow]

What is happening is the ground is looking for the path of least resistance. Currently (pun intended) it is you. This is potentially a life endangering situation. Check the building's ground, check all the power cords and keep on checking until you no longer get a shock. This is a serious problem. I had a friend just put a windscreen on the mic and he did an outdoor show on damp grass. Needless to say, he got knocked on his ass and his DI blew up like a bomb. It just happened to be sitting on a screw on the top of his amp. Turns out that one of the venue supplied power cords had the ground plug removed so they could plug it into a closer 2 prong outlet. Things could have been a lot worse but do not ignore those little shocks.

 

I do not believe it has anything to do with phantom power but I would suggest that you do try to find out why that is happening.

[scarecrowbob]

Is the guitar amp plugged into the same circuit as the PA?

[Miko Man]

I respectfully suggest that your trouble-shooting start as far "up-stream" as possible, since a faulty or non-existant ground is a possibility. That would be at the wall receptical where you are plugging in to the AC service. Besides a standard outlet tester, you should check with a non-contact voltage tester to make sure that the ground wire isn't tied to something it shouldn't be.

 

If the venue's power checks out OK, then you can move "downstream" in the connection chain for each separate item that is connected to the AC service. If you are not sure of what you are doing and how to safely make tests, I urge that you obtain the services of a qualified person. Mark C.

[W. M. Hellinger]

 

he got knocked on his ass and his DI blew up like a bomb. It just happened to be sitting on a screw on the top of his amp. Turns out that one of the venue supplied power cords had the ground plug removed so they could plug it into a closer 2 prong outlet.

 

Ah, yes... brings up a good point.

 

I'll suggest the removal (cutting off) of the "ground lug" in itself was doubtfully the immediate cause of the effect.

 

I'll suggest that some (possibly many or most) don't realize the entirety of the problem with hacking the ground lug off an extension cord, being: 2 prong outlets (1-15R) are polarized (one of the two sockets is markedly bigger than the other)... and dedicated 2 prong plugs on 2 conductor power cords where the polarity matters, those plugs are similarly polarized, (one of the prongs is markedly bigger than the other) because: Generally (or at least it's the intent) a 2 prong plug, where the polarity matters, cannot be plugged into a 2 prong (or 3 prong 5-15R) outlet backwards... where backwards would result in swapping the neutral and load to the device. 3 prong plugs (5-15P) are polarized by virtue of the fact that with the ground lug intact, the 5-15P can only be plugged into a 5-15R one way... and can't be plugged into a 1-15R at-all. However, a 3 prong (5-15P) plug... the neutral and load prongs are generally the same size... so hacking the ground lug off the 3 prong (5-15P) plug opens up two problems:

 

1) eliminates the safety ground connection (generally safety stuff exists for a reason), and:

 

2) eliminates the polarization of the plug... thus allowing the plug to be plugged into 1-15R, 5-15R, and 5-12R outlets willy-nilly in relationship to the intended polarization of the connection... immediately creating a 50/50 chance of swapping the neutral and load being fed to the device... being a double jeopardy situation. Really heinous.

 

I strongly suggest, if you run across an extension cord at a jobsite that

[Mike Riley]

 

Okay, thanks, got it. For the record, this is happening both with my Telecaster, which is runing into a new Princeton Reverb Reissue and with my banjo, which is running through a DI directly into the board, so the problem is not the amp. Perhaps a powerstrip is not properly grounded?

 

 

You can purchase one that will inform you if there is a fault in the system/poor grounding good investment I use only it and I will not use a circuit that does not come up clean.It like 5bucks more you can get at walmart

[Jersey Jack]

 

Is the guitar amp plugged into the same circuit as the PA?

 

 

Initially, yes. I then moved the amp to a different outlet, but I'm not sure that it's on a different circuit.

 

This is happening in my house, by the way, not in a venue. And it's in a newly renovated area, which had an electrical inspection at the conclusion of the job, so I doubt that there's faulty wiring.

[Mutha Goose]

> It happens with your guitar through the amp AND your banjo w/o the amp: Probably not the amp

though this could be checked a little more thoroughly

 

It appears like the only variable you haven't tried changing is the PA or something in the mic path....

[nchangin]

Mixer grouned to same place as everything else?

[W. M. Hellinger]

 

This is happening in my house, by the way, not in a venue. And it's in a newly renovated area, which had an electrical inspection at the conclusion of the job, so I doubt that there's faulty wiring.

 

uh...

 

I've been a witness to countless electrical inspections (probably >100). To date I have yet to see an electrical inspector actually test an outlet... nadda, zip, zero.

 

I have no idea one way or another what passes for electrical inspections in your area, and therefore I have no idea what your confidence level should be in untested outlets... but based on my experience, I certainly wouldn't rule out faulty AC wiring (based on renovated and inspected house wiring, or otherwise)... in-fact, my knee-jerk reaction is the exact opposite.

 

Ignorance about this sort of thing is probably bliss... till you have a reason to have suspect. Actually, ignorance about most everything is probably bliss... but we probably don't want to go there.

 

I'll suggest that if you're intent on solving a problem, then assume nothing. Rule-out that which you understand the odds (and you're extremely confident lays beyond 3 sigma outside of plausable), or know how to test to conclusively rule-out and have personally done what it takes to rule that out.

[agedhorse]

This is the FIRST place I would start looking at. And immediately too.

 

 

uh... I've been a witness to countless electrical inspections (probably >100). To date I have yet to see an electrical inspector actually test an outlet... nadda, zip, zero. I have no idea one way or another what passes for electrical inspections in your area, and therefore I have no idea what your confidence level should be in untested outlets... but based on my experience, I certainly wouldn't rule out faulty AC wiring (based on renovated and inspected house wiring, or otherwise)... in-fact, my knee-jerk reaction is the exact opposite. Ignorance about this sort of thing is probably bliss... till you have a reason to have suspect. Actually, ignorance about most everything is probably bliss... but we probably don't want to go there. I'll suggest that if you're intent on solving a problem, then assume nothing. Rule-out that which you understand the odds (and you're extremely confident lays beyond 3 sigma outside of plausable), or know how to test to conclusively rule-out and have personally done what it takes to rule that out.

 

[jwlussow]

Interesting point. I (or should I say, my ex-wife) just had an addition done. The electrical inspection consisted of counting the number of outlets to make sure there were enough to meet code and looking at the termination at the new electrical panel. He never checked a single outlet.