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A shocking experience!

baddarryl

baddarryl

Oct 26, 2008
1,738
1,537
Cape Fear!
#1
So I bought a used Ashdown last week and am wondering what caused this. I have a lamp with a metal pull chain attached to it that is plugged into the same receptacle as the amp. Apparently I was still holding the strings on by bass as I went to turn the light on and blaaaam..........shocked the crap out of me. Was I a conductor or what? I could feel it travel from the hand that pulled the chain to the one on my fingerboard. Still tingles actually. Do I have a bad ground or something somewhere? Could it be the amp? I would hate to be playing, touch a microphone and blow up onstage. Cool looking, but no fun!
 
#2
Glad you are OK. Yes you were a conductor. This is the most dangerous possible case where the current passes through your chest. Could be the amp, the lamp, or the outlet wiring. It is worth getting to the bottom of the problem, but don't get hurt trying to figure it out.
 
#3
Ah, house current.

You can get an outlet tester for cheap at the hardware store (worth keeping in your cable bag to check out suspicious new stages). That will let you know if your wall outlet is OK. I would also suspect the lamp - those things can be easy to rewire... incorrectly.

I'd be a bit surprised if it was the amp, but you never know.
 
#4
Do you feel strangely calm now? :) I got jolted really badly once and then felt stoned for the rest of the evening... might have just been my happiness to be alive.

What I learned from my experience; When a sticker in the back of an amp says there's a risk of electrical shock, they're telling the truth. Don't mess in there with the head plugged in.

Glad you're OK.
 
#5
99% it's the lamp.....

2 things that happen.......

1) the paper insulation tube between the lamp screw-in part and the outer metal shell gets broken or tears..... letting the shell touch the metal when you yank the pull-chain.

2) the lamp doesn't have a polarized plug (or is mis-wired), and gets plugged-in so the screw-shell is hot..... (the little center part is supposed to be hot, and the screw-shell on the neutral)

it's a stupid construction, from about 1900, but there are millions of them out there.....
 
#6
dude, you realy wouldnt die from something like that unless it was a capacitor or a transformer on the amp, the wall outlet is only 120v AC, therefor you would get a pretty good shock but nothing too dangerous like a computer power supply or something, it could be a bad ground in which you were the ground, try to plug it in a different outlet and touch the lamp. DONT TOUCH THE CIRCUIT BOARD OF YOUR AMP, without shorting it out with tin foil first, and when doing so only use one hand never 2 at the same time, i suggest keeping 1 behind your back, and dont even try if you dont know what youre doing
 
#8
LetsCountRox said:
dude, you realy wouldnt die from something like that unless it was a capacitor or a transformer on the amp, the wall outlet is only 120v AC, therefor you would get a pretty good shock but nothing too dangerous like a computer power supply or something, it could be a bad ground in which you were the ground, try to plug it in a different outlet and touch the lamp. DONT TOUCH THE CIRCUIT BOARD OF YOUR AMP, without shorting it out with tin foil first, and when doing so only use one hand never 2 at the same time, i suggest keeping 1 behind your back, and dont even try if you dont know what youre doing
Click to expand...

Actually, you could die from household 120v current due to ventricular fibrillation, or muscle paralysis with secondary asphyxia.

I've gotten some NASTY shocks from household current before - hand was numb for a day or two, my arm up to my elbow lost feeling for a few hours. Scary stuff. I'd have an electrician come and check that outlet out.
 
#9
yeah you could, but its only if your a really good conductor, but that can change from day to day, often in the winter your more cnductive tan summer due to more moisture in the air that acts as some what of a resistor.you really got to watch for comp pwer supllies, and tube tv, and monitors, even amps, they store like 25,000v
 
#11
This is part of the reason I use a foam pop filter on my mic ...only took once or twice to get zapped on the lips to figure out I didn't like it. :D

Back in the 80's in an electronics class I think I remember learning that most injuries from electric shock comes from the body reflex in response to the shock, as you jerk back your arm and hit your hand on something ....or throws you off balance and you hit your head on an amp rack ...or any of a variety of actions.

As another poster mentioned, you can also die from 120, though usually not the case. Either way, keep one of those outlet testers in your gig bag ...and use it before you plug in.
 
#12
Rick Auricchio said:
Not true, Rox.

If there is 120v on the lamp housing and the amplifier is grounded via its 3-prong plug, then current flows from lamp to strings to ground.

If the lamp had a 3-prong plug (they don't), then the lamp would have blown the circuit.
Click to expand...

That seems like it, but what if the same lamp is plugged into another outlet on the same circuit? Does it only act like a loop through the same receptacle as you described? And no way, I am not about to test this again! I once grabbed a well pump that was improperly grounded (230V) and damn near couldn't let go of it. I only dance with the devil once in a while ya know? I will also get an outlet tester to be double sure. Thanks all.
 
#15
One of the worst electric shocks I ever got was I was 16 years old and was working on a RADIO power amp I had built from surplus parts. It had old mercury vapor rectifiers in the power supply and I didnt want to pull the tubes but needed to get under the chassis.

I took a small 5VAC power supply I had and heated up the filaments on the rectifiers and flipped the chassis. I then proceeded to have my hand jump all over the inside of the power supply, ***? Well 5 volts back fed the filament transformer, which was in parallel with the plate transformer on the line when the power switches were on...

2000V of DC not quite full power (2500) but quite a roar considering 5V was feeding it. Never made that mistake again.

Ah ROX you keep thinking house power can't kill you and we'll be sending flowers, 1966 my best friend's Dad electrocuted by his electric drill in the driveway while working on his car. This was before double insulation on household power tools. Obviously one side of the line went to the metal case of the drill. POOF. Dead.

This stuff happens everyday.. I had a piece of radio gear try and kill me a couple years ago. Line to ground bypass cap was shorted and there was a bunch of juice on the chassis. I reached behind the rig to hook up an antenna and about blew my ass off.

Actually three wire cords are supposed to save you... But half our equipment around the house is two wire gear. When you mix three wire equipment with two wire stuff you are ACTUALLY at higher risk than if you only had two wire gear around.

Thats the funny thing about electricity it'll kill you when you least expect it

BOB
 
#16
Be careful.


Check polarity of lamp.

Check outlet Polarity and Ground present.

Be careful.



Man I got the crap knocked out of me the other day at a gig. Soundman dosnt have the PA grounded I step up to da mic to a sound check and Whamo. Ouch. I had tested my outlet I had my rig in but not the PA. SON OB A GUN!

I got hit with 660 volts Delta once.

Be careful.

AC will kill you, DC will kill you deader then hell.

I have a Welder that will put out 60 volts at 600 amps. It will turn you into Popcorn if ya aint careful.

Be carful.
 
#17
LetsCountRox said:
dude, you realy wouldnt die from something like that unless it was a capacitor or a transformer on the amp, the wall outlet is only 120v AC,
Click to expand...


Wrongo !


Keith Relf:
The Yardbirds
Richmond, Surrey, England, 14 May 1976; vocals/harmonica. Relf was fatally electrocuted on stage .

Les Harvey:
Stone The Crows
3 May 1972
died after being electrocuted on stage at Swansea's Top Rank Ballroom. .

John Rostill:
The Shadows
Rostill was fatally electrocuted while playing his guitar.
 
#18
LetsCountRox said:
dude, you realy wouldnt die from something like that unless it was a capacitor or a transformer on the amp, the wall outlet is only 120v AC, therefor you would get a pretty good shock but nothing too dangerous like a computer power supply or something, it could be a bad ground in which you were the ground, try to plug it in a different outlet and touch the lamp. DONT TOUCH THE CIRCUIT BOARD OF YOUR AMP, without shorting it out with tin foil first, and when doing so only use one hand never 2 at the same time, i suggest keeping 1 behind your back, and dont even try if you dont know what youre doing
Click to expand...

Technically, you could die just by licking the terminals on a 9v battery. This is true (albeit rare).
 

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