Shock Hazards Associated with Electric Guitars and Amps
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- Опубліковано 4 лип 2024
- This is a discussion of the shock hazards associated with electric guitars and amplifiers, created in response to comments and questions received after I posted the Death Capacitor video. In it, I explain the source and nature of the shock hazards and how to avoid and eliminate them. I hope this information is both interesting and informative, and helps to spare you from a painful shock....or worse.
If you enjoy videos featuring classic vintage guitar amplifiers, jukeboxes, and exotic electronic gadgets, then please subscribe to my channel....if you have not already done so. You will gain immediate access to over 60 (hopefully) interesting and informative videos, and you will be notified each time a new video is released.
Thanks for watching !!!
Every guitarist should watch this vid. Thanks for this information.
You're welcome, Wm.
Learned my lesson tonight and im still a little shaken up from it. playing with headphones plugged into the amp (3 prong) hear some extra static so I go to turn off a small lamp hand gets close to the lamp (2 prong) and bam! muscles tighten up so hard I couldnt even let go of the damn thing until i moved far enough it unplugged and fell out of my hand. probably one of the scariest moment of my life.
Wow.....what a bad experience, PP. I had a similar one many years ago and actually experienced heart palpitations. We hope you resolve the wiring issue and never have a repeat of this scary event.
I had this just today for the first time! super scary. Should've seen this video beforehand!
I wonder if you ever were a teacher or training instructor, your explanations are very well planed and comprehensive, congrats.
Yes, I was a math and science teacher for 16 years, Javier. Thanks for your very kind comments :)
Uncle Doug
You still have it Mr Doug, I always enjoy a good class or explanation and your videos are some of the best I have seen on you tube. I also enjoy your video on building the finger joined amp, a friend of mine and myself wanna build a custom cab and that is a delux explanation.
Thanks so much, Javier, and best of luck with your cabinet-building project.
@@UncleDoug Completely off the subject of your video, but I can tell you from experience that the best teachers seem to be people that actually were in the industry that they try to teach about. So much more to be learned by experience than from the teacher that just knows the answers to the questions from the book. Four years of math from teachers in high school and the things that stuck with me and made sense were the ones taught by a teacher who was a contractor on the side, he showed how the math actually worked in the real world.
@@mitch3064 Yes, great teachers cover every learning style. Doug is a great teacher.
20 years ago, during a jam session in my friends garage, the bass player and I accidentally let our strings touch. He didnt have his fingers on the strings, but I did. I got a big shock and went blind and deaf for about 15 seconds and the reverb unit in my Ampeg head didnt work anymore after that. I assumed one of our amps was screwed up but I never investigated. I used that amp for years after and never had an issue, so I guess it was the old Kustom bass head
Hopefully, our video will help to prevent accidents like this in the future, Steve. Thanks for your input.
I think Steve's hair tells the story.
Does anybody remember when Ace Frehley got shocked in Florida at a show and he wrote the song shock me.
Barefoot on a summer day getting ready to jam in the garage in my high school days, I got the shock of my life from a sketchy amp. That amp speaker later caught fire during a rehearsal!
Very informative.. your videos are the most understandable and interesting I've been able to find on UA-cam about old tube amps. And by the way your drawing isn't too bad either, I love your sense of humor. Thanks...for passing on your knowledge and years of experience.
This is a really great video and more people should know the risk.
I bought a second hand bass amp in the past couple of weeks with the standard 3 pin plug we use here in the UK. The plug was a white masterplug branded one which told me it had been replaced at some point in the past 20 years.
Something told me to check it out, and sure enough, only the live and neutral wires were connected, and the earth wire was loose inside the plug.
When I played the amp before checking the plug, I definitely felt the slightest tingling just as I first touched the strings but nothing else. It was at the point where I thought I might be imaginging it because I saw the plug and was suspicious and knew this is possible, but checking the plug confirmed my suspicions.
Thanks, S2. I'm glad you repaired the plug before suffering any harm.
Hi I did a dep for my friends band on bass in the eighties, they had a dep guitarist and also the original guitarist that had suffered an electric shock he told me he could not play all the bands material and showed me why , parts of some of his fingers got burnt into from the shock from the strings and were still healing, they checked all their gear and narrowed it down to a loose earth wire on an extension cable. After that I used to solder every wire on all my three prong mains plugs and not rely on the daft little screws to hold the wires in place.
work of art man
your videos are really educating me! thanks!
You're welcome, Danny. We're glad to hear that the videos are helpful.
Perfectly clear,thanks!
Thanks again for watching, Ron. Good luck with your own project(s).
Great explanation!
You can blow yourself off stage pretty good with bad venue/equipment wiring.
I've toured thru venues with artists, and measured 120V and 220V between a guitar and mic. Sometimes I'd find it myself during setup, other times one of my artists would get it during soundcheck.
I encourage guitar players to invest in a quality wireless systems for their rigs if they're touring. For me, it's a wise investment, simply for the sake of keeping the artist out of the electrical circuit. Typically we keep a few channels of "disposable" wireless around in case we find ourselves doing shows in the rain. Throw the wireless packs in a condom and play the show. Sweaty guitar players are typically harder on gear than the rain.
Thanks, DG. Very interesting......I can definitely see the advantage of wireless gear. We appreciate your input.
Thank you Uncle Doug.
Definitely some "shocking" information !
I hope a lot of musicians, especially young ones starting bands see this
very important information that you are providing.
Most mics are isolated from the stand by the plastic mic clips (or holders),
so I always touch the guitar strings to the mic itself, or I just touch the mic with my hand, with the other hand on the guitar strings, checking for any "tingle".
Also make sure your mic stand has all of its rubber feet & are in good condition.
If the feet are worn down to where the metal screws (that attach the feet to the
metal base) are contacting the ground, then the entire mic stand is a path to ground.
I've been zapped while holding my guitar & grabbing a mic stand. It was missing one of it's 3 rubber feet, so the metal base was touching the ground.
Once I had a blue spark from the mic to my front tooth. It almost knocked me out, going right up through the tooth nerve hurt like hell. Not a good place to get shocked.
Since then I check at every gig, especially since there's a different sound company & sound system at each gig.
Greeting, Brian, and thanks for your input on this subject. As a performing musician, your experiences and warnings are especially beneficial to others who face shock hazards with guitars, microphones, and stands. The shock to the front tooth story sent shivers up my spine..... :O
SO important, Uncle Doug! Thanks for spreading the word!
It's our pleasure to do so, Thomas.
I have re-watched this video a few times, and it all finally came together. Thanks for the great informative video Uncle Doug.
You're welcome, JJ. One advantage of YT videos is the ability to repeat portions that require additional study. We're glad it worked for you :)
Greetings, Ron. I believe all electrical devices in the US also come either with 3-wire, grounded plugs or polarized plugs, and have for many years. The issue of two-wire plugs arises when you start dealing with vintage amplifiers, made before the safety rules were written and enforced.
Troy, your inquiry was posted without any reply capability, so I will try to answer here. First off, since your house wiring does not have 3-wire, grounded sockets, I'm not real optimistic about it ever being completely safe, and the penny-shorted fuse box is a disaster in the making. You need to have an electrician check your outlets, especially in the room where amps are plugged in, and install either 3-wire grounded sockets or, at least, polarized 2-wire sockets. The fuse box needs to be checked and all pennies removed.
The amp needs a new power cord with a plug that matches your (new) sockets....either polarized 2-wire (hot wire to hot wire) or 3-wire grounded. The Polarity switch needs to be bypassed so the hot wire stays hot. There may be a short to the chassis within the amp that needs to be repaired (perhaps the "Death Cap" is shorted ?). After it's done, the amp needs to be plugged into your (new) socket(s) and tested for any potential between the chassis and a house ground (i.e. a cold water pipe). If there is none, then you are most likely going to be OK.
Greetings, Keith. Yes, a properly functioning death cap will pass a wee bit of AC to the chassis, but at extremely low current levels (picoamps?). If there is a 3-wire cord, it passes harmlessly to ground. In Troy's case, with no grounded outlets, this could conceivably be a problem.
Re the rubber-soled shoes, charging a "capacitor" with a half-inch-thick dialectric would require (tens of) thousands of volts (i.e. static electricity from a new carpet). Also, wall current is AC, which passes through caps....charging them requires DC.
Uncle Doug, I don't know if you get notified every time anybody posts anything anywhere in this comment thread, but I just posted a couple of shocking scenarios that happened to me personally at the very top of the comment thread, not specifically to you but to everyone. You should check them out.
Thanks for the straightforward advice. Very informative.
You're welcome, Milo.....glad it was helpful.
Fantastic video. Thanks so much for help keeping us all safe.
You're welcome, Gordon.
Hello! This video has been really helpful!
I wanted to tell you about the problem that i've been having with my equipment. Maybe you could help me find out what seems to be the malfunction..
Recently i bought a brand new electric guitar and an used 10w amp (this because of budget issues haha) and i've been experiencing electric shocks whenever I touch the power switch of the amp. This amplifier has the three plugs.
What i've noticed in these couple of days since I bought all of this equipment, is that I get the shock when I touch the amp (while is connected to an extension where I also connect my PC, the monitor and desk lamp) at the same time that i'm grabbing my guitar..
I plugged the amp directly to a socket and did'nt receive any shock that way.. but in reality i'm a little afraid to confirm it again..
What are your thoughts? I'd really appreciate if you could help because this has been kind of a bummer
Does the extension cord have 3 wires.....or two? Most have only two and do not provide any grounding capability. If no shocks occur when you plug the amp directly into the wall, then this is the ONLY way it should be plugged. I have no idea what type of amp this is, but it seems to have internal grounding issues that may need to be addressed.
@@UncleDoug the extension i've been using has three wires and this has been happening only with the Amp. I have also connected my pc and monitor to this extension and never gave me any problem.
And the Amp I bought is a Vox pathfinder 10, wich i got from a local music store in very good conditions and used!
@@gabo_caruso If there is no shock when the amp is plugged into the wall, but there is a shock when you use an extension cord, then it would seem that the cord, regardless of how many wires it seems to have, must be the cause. The PC has an insulated body and would not be a reliable comparison.
@@UncleDoug Today I tried both ways: Amp connected to the extension and then connected to the wall. And in both ways I felt current coming out of the amp's chassis (doesn't hurt or anything), specially when I put my finger over the power switch. Also happens with or without the guitar plugged to the amp..
There must be something wrong inside the amp i guess.. But the weirdest thing is that in the music shop, this didn't happened at all.. It's happening where I live.
Anyways, your responses have been very helpful! I really appreciate it!
@@gabo_caruso Your electrical receptacles may not be wired properly, Gabe. You can buy a cheap device at Home Depot and test them.
Have you seen the video by "Woodeso's guitar mods?" This guy has his left hand on his strings than grabs an ungrounded metal lamp post and gets zapped. He broke loose by falling and knocking it loose from his hand. This goof ball doesn't even know why it happened and thought it was funny so he still has the video available to watch...you should probably give him a heads up and tell him about the death of Keith Relf from the yardbirds.
+Steven Spencer This guy sounds like a good candidate for the Darwin Awards, Steven. I'll try to find the video.
Late, but let's hope this is a still useful reply:
ua-cam.com/video/trY4lNdz-ks/v-deo.html
@@UncleDoug here is the video, electric shock occurs shortly after 3 minutes and 30 seconds: ua-cam.com/video/trY4lNdz-ks/v-deo.html
Very interesting. Thanks for being so clear
You're welcome, Andrew.
Hello again! This is a good video for many players to watch...I try to explain this to many guitarists who's amps I repair, but they look at me funny :) I tend to explain it tech terms and sometimes I don't realize it and think I'm talking to another tech...But this video explains it in simple comprehensive terms for the non-tech person...another great video! :)
Musician Safety: Touch your plugged in guitar (strings) to the Mic stand & see if it arcs.
If it does, don't touch it. Call a Licensed electrician.
Good advice, C&C.
shocking Uncle Doug
Very good information! Thanks for all of the videos you've posted.
zarbog8 61 You're welcome, Z. Thanks for watching :)
Thank you so much! I got shocked recently at home while playing guitar and this video helps my on my way to understand how all of this works and how to remedy the situation. Nice drawing by the way :)
You're welcome, Rurzan. I'm glad the video (and drawing :)) were informative.
kiss of death
An excellent suggestion......GFI's are a great safety measure. Thanks, Frank.
Thanks, TG. I really appreciate your kind appraisal, and you are quite welcome.
Thanks Unk, once again you gave out some great info, very informative for sure.
You're welcome, Ron.
Thanks for answering my questions!
Greetings again, AG. I think getting a fuse installed would be a great idea. The selection of proper value for the fuse is important also. Be sure to use the lowest value (in Amps) that will still allow the amp to function, and I think that rapid-acting fuses provide more safety than slo-blo's. Good luck !!!
Thanks for your kind words, AG. I'm very glad that you are enjoying the videos.
One os the best videos for musicians ever !
Thanks, OB....glad you found it helpful :)
This was such an important and well done video. Thank you. You couldve saved lives.
You're welcome, GT. I sure hope so :)
Thanks to your channel and Mr Carlson’s Lab, I have really learnt a lot. Thanks for sharing your knowledge.
You're welcome, P.
makes perfect sense - will do the test before the amp is serviced and then again, to see if there has a hazard from the field coil or any other parts and then after as well. i should be sure then.
thank you for the great videos you've been making - they way. it is a great library of historical amps and also very educating.
with tis words i'll say "greetings ;)"
thanks Doug, for your reply. this problem did never come up for me, although as a 55 year old chap that did my elec tech college back in the mid 70s, which we did fault finding on valve tv's and radios. I always remember one of many things that the lecture said at the beginning of the year :- you will find a question in the test exam at the end of the year that will sound silly. This is that question (the best as i can remember it).
This video has been truly helpful, thank you really much!!! 😁
That's great to hear, Caine.
Was just reminded of Kieth Relf. And bingo-you explain it beautifully. Thank you. Good to remember.
Our pleasure, PW.
Thanks, Frank, I value your opinion and your approval means a lot.
Great video. I was shocked to see my exact guitar and amp in the video. Good taste Uncle Doug, and awesome important info.
Thanks, Tom. Be safe :)
Thank you SO VERY MUCH. My 8 and 9 year old grandkids got into music this past year. I bought my granddaughter a Martin electric acoustic, mic & stand, and a small Fender practice amp. She wants to be a singer like her GrandMaMah who’s been performing since age 3. By age 5, her GrandMaMah was taught about this. EXTREMELY portant
You're welcome, Elaine. It's never too young to learn about electrical hazards and ways to avoid them.
Uncle Doug sounds like my old electric Shop teacher from way back . . . Thanks Uncle Doug . . . this is always good refresher info. Uncle Doug is saving lives and keeping guitarists safe like a world-wide Lifeguard. Thanks man.
You're welcome, Dr. R :)
Really nice explanation!! Thank you so much. :)
You're welcome, JJ :)
this is hella interesting and the only good video i have found on this topic.thanks for making it
You're quite welcome. Thanks for posting such a nice comment :)
This is exactly the video I was looking for
We're glad you found it/us, Map.
I'll never forget at a practice in an old warehouse in jacksonvile florida got an arc from the mic and the lights dimmed, ouch! I hate when that happens
I'm surprised you survived, David. To dim the lights, the current draw must have been substantial, and it only takes 100mA or so to kill human.
Thanks for the PSA!
You're welcome, Riloh. We care about our viewers :)
Uncle Doug- splendid presentation! I'm grabbing my multimeter right now. Thanks, man.
Thanks, AG. I hope the reading is 0V :)
Another great video Uncle Doug."Steve Stevens" hairdo was classic.
This is a great video. I was just shocked trying to plug a cable from my amp into a keyboard. This video helped me understand what happened. In my basement, I had just carpet cleaned. So the carpet was wet, even though I put a towel on top of the spot I had just washed. I didnt think twice and was barefoot. On top of that, my receptacles are not grounded, I have to use the three prong to two prong adapter. Perfect storm for getting shocked. I was at first unsure if the cable actually shocked me and I picked it up a second time just to get shocked even more. It was quite startling and an eye opener. Thanks!
You're welcome, James. We're glad to hear that the video has enabled you to identify and eliminate shock hazards. Best wishes for a safe new year.
great video!!!!!!
thank you!
You're welcome :)
Doug loving the work keep it up, and thank for all your hard work, there should be less accidence. I have a old project that i bought all the valves for, and must get back to you have reminded me of thanks. (the project is a mic and guitar 2 i/p valve amp 30 watts as i can remember.) and on your reverb spring project i used to have a old mixer desk with on in, now where did that go (prob lent to a friend and forgot about it).
wonderful, just wonderful explanation uncle D.
I'm glad you liked it, PJ.
@@UncleDoug You make my girlfriend and me laugh out loud with your videos, just wonderful haha. And we love to learn.
Myself I dived in the world of cables and the results are stunning. I can honestly say that your knowledge is starting play a bigger part in my understanding of electronics. Just tube circuitry is fascinating as well. I see a lot of DIY pedal/ amp builders on Facebook who would love this....
@@Projacked1 That's good to hear, PJ. Our best to you and the spouse.
Andy, since you converted the Electar to a three-wire power cable, it would be a good idea to install a fuse in the "hot" (black) wire, so that if a short circuit does occur, the fuse will blow and save your precious wiring, transformer, and (maybe) life.
thnx for this valuable information. I had an electric shock while playing guitar.
You're welcome. Now, hopefully, you know why.
Very well explained
Thanks, Paul :)
Excellent video, I've got to say!
Thanks :) We have 150 more such videos that you may find interesting. Thanks for watching.
Welcome aboard, Steve !! :)
Nice video. I especially liked your drawing of Steve Stevens. :D
As for touching the guitar strings to a mic stand to see if there is an arc, that might not work as much today because most mic clips are rubber or plastic and only the mic is connected to ground via the cable.
Brad Linzy Thanks, Brad. I guess if that's the case, you would need to touch a metal part of the microphone itself to the strings. Maybe they should simply make the stand and external parts of a microphone out of plastic and eliminate the problem altogether :)
^Genius above!
This is what I learned to do a long time ago, while not touching anything but the wood, lightly rub my bass strings across the metal pop screen of the mic and look & listen.
Great vid, a few weeks ago I was rehearsing with my band, playing bass and singing, and at some point I touched the microphone with my lips and got the electrical shock of my life. It stunned me for a few minutes and they just laughed, although it was really serious for me. I have a spare multimeter that I'll be using to test the potential between the strings and the microphone from now on ;)
Pedro, I'm glad that no injury resulted from your run-in with inadequately-grounded, reversed-polarity equipment, but your experience really emphasizes the need for three-wire, grounded power cords and greater awareness of shock hazards. Thanks for sharing this cautionary tale with us, and best of luck for a "shockless" future :)
Good information here! I've had the privilege of playing in a very good little band in the 60's on what was then brand new equipment. All amps had two prong plugs (usa) and PA systems, etc. We did a few grand openings outdoors on a cement slab. What saved our lives was knowing how to set the ground (polarity) switches on our amps. The procedure is easy, just touch the tip of a guitar plug volume turned low, listen for hum, flip the GND switch for the least hum. This effectively connects the chassis to the neutral side of the outlet. When all amps are "grounded" to neutral, the shock hazard is eliminated... barring any internal malfunction in the amp. All of that said, the safest AC mains connection is with the three prong plug.
Thanks, FG. Actually neither plug position connects either side of the primary AC circuit directly to the chassis. The ground switch enabled you to connect the "hot" AC lead to a capacitor that allowed noise in the line to go to ground before it reached the power transformer winding. As long as this capacitor had no internal short circuit, the chassis was effectively insulated from the primary AC circuit and there was no shock hazard. Your synchronization of equipment polarity was wise, however, since it effectively eliminated any potential between the different chassis, which could cause a shock hazard. As you say, 3-wire chassis-grounding power cords are definitely the way to go.
Been there. For me, the show came to a stop until things were sorted out. In dive bars where things were too weird, we either did a straight acoustic show or we cancelled.
.....and due to concern for your own well-being, you are still with us, Michael, and able to make comments on our videos. We're glad :)
very informative
Thanks, Chris :)
where the power cord enters the chassis, thru the switches, fuse holder, and primary winding of the power transformer. It is even more likely in amps that have no power transformer, because the AC travels throughout the amp chassis and the possibility of shorts is much greater. I hope this makes sense.
I wouldn't think that the field coil of the speaker would be a hazard, but if one shocked you, then maybe so in the case of this unusual amplifier. You can test it with a voltmeter like I do in the Death Capacitor video. Connect one lead of the voltmeter to a good ground and then touch the other lead to metal parts of your amp when it is plugged in and turned on. If there is any shock hazard, the meter will give a reading of the amount of voltage present in the chassis and speaker.
I can understand why a musician, faced with an audience expecting him to perform, would resort to drastic measures to keep his malfunctioning amp powered up.....but what a price to pay. This experience would definitely inspire me to have a few spare amps handy if I were ever in Mr. Harvey's shoes.
Thanks for this
You're welcome, LB. Please be careful.
Thanks for this video, Doug. My personal philosophy is -- originality be damned, any piece of vintage equipment I have gets a proper grounded plug. I learned my lesson many years ago when I had the "ground" switch flipped the wrong way and high-fived my bandmate after a particularly awesome rendition of Into The Void.
Jason Thorpe I understand, Jason, and agree that any equipment that will be used commercially definitely should have a grounded, three-wire cord. On pristine, vintage equipment, receiving limited use at home and in controlled conditions, I tend to favor originality, as long as the precautions I have described are followed.
A topic not talked about enough. Thank you. The danger is very real.
Thanks, CH :)
🔥 this is a very very overlooked subject and I'll never forget the shock I got off my 1970 200 watt Marshall major because of that pin plug for the ohm adjustment bounced out was not a good scenario
Thanks, Charles. Glad you survived :)
@@UncleDoug you are the best Uncle Doug🤞💜
Just checked! Mounted the GND of my school DC-power supply to the multimeter and the other cable to the guitar strings. 0 Volts! Then I remembered that I should probably check for AC. Bam. 20 Volts! (Vox VT20X - so that's where the 20 comes from)
Impressive and greatly explained video. Thank you very much!
You're welcome, Marco. Glad the video was helpful.
Thanks!!
You're welcome, Juan.
Important! (Oops) Thanks again for illustrations, also! Love it.
You're welcome, Elaine :)
Yep that explains it! I was bare footed every time on the polished concrete floor of my garage! Got shocks from the strings after playing my Strat appx 10 mins. I was using a Vox mini practice amp with a 9V DC adaptor. Thanks for the explanation.
Rusty and I are glad to hear that the video was helpful, L1. Thanks for watching and commenting :)
lanthaniated1, Hmm, now how could this happen? the only way I can see that you would get shocks from a 9 volt wall wart adapter is if it was seriously defective or seriously designed him properly. Perhaps it uses a transformerless "switching" power supply? and/ or was additionally defective? a different wall wart adapter might cure this problem. here's a hint, if the 9 volt adapter seems very lightweight like it's all plastic almost, it's probably a switching Supply. Anything with an actual Transformer is going to be a bit heavier. The switching supply will have some inductor coils in it but usually it's not very big on the copper wire content nor does it have the steel core necessary for a Transformer.
I remember being taught about the perils of earth lifting in venues, especially if being put under a lot of pressure to remove a hum somewhere. I think part of what was said, was that you could well have your own gear properly configured, but the risk turns out to be further down the chain, because you've been hooked up to a lifted earth. The more that get lifted, the greater potential for disaster etc.
You're right, AK. You're equipment may be in great shape, but the moment you connect to an unknown power supply or to the equipment of other (less conscientious) people, you are at risk. Toss in a metal floor and/or moisture, and the situation could become lethal.
Hi uncle Doug about 35 years ago I experienced this. thank you for putting this out to musicians and techs,I was in our studio with our singer the whole rm was covered with carpet summer day hot as hell sweating my guitar strings welded to the mic stand. my lips touch my mic to sing and boom blue ⚡️ sparks I tried to scream nothing came out I was picked up an thrown against a old wooden chair that broke to pieces my singer told me what happened when I came to the polarity on his PA and my amp had changed. I didn't feel so good and didn't play guitar for a week . I guess I'm Lucky to be alive ...thank you for your top notch videos I love em...
You're welcome, LL. We're glad you survived this ordeal and took the time to warn others about the shock hazards associated with polarity differences in equipment.
Thank you and Rusty
😆😆 I have been shocked by a microphone a few times. I got in the habit of touching my guitar strings to the mic before I go to sing. Great video.
Thanks, IG. Continued good luck.
Yes, Uncle Doug. I had the mic thing happen. Had my Les Paul Gold Top plugged into my 100 watt Ampeg V4. I boldly stepped up to the mic to sing, when out of nowhere, a purple caterpillar appeared and jumped from the mic to my upper lip. It bit me and vanished just as suddenly. I started singing the song a cadence later, and did so from six inches away. Stuff like this used to happen all the time, and we usually held our plugged in guitar in one hand and smacked at the mic stand and each other to check for a current differential. It was the poor kid's volt meter.
By the way, heard Rusty's guitar solo on one of your other videos. It was masterful.
Addy Adderson Greetings, Addy. Thanks for sharing your "shocking" experience with mixed polarity in musical equipment. The "poor kid's volt meter" analogy was great :) Rusty sends his regards and appreciation for your kind appraisal of his musical skills :) ^. .^
Anything you say is 100% correct and relevant; however I prefer to talk intensity and resistance, which are easier to understand for most people:
a) the danger is current intensity for the human body: 30 mA, across the chest, cause muscles tetanization (heart and lungs blocking, inducing terminal syncopes and rapid brain melting)
b) the human body resistance varies between 100 ohms and 1000 ohms (depending of your health condition , weariness and stomach content)
* most deadly electric shocks occur between 11-12 am and 17-18 pm when workers are hungry (official accident stats in french data base)
So a tension of 0.03x1000 = 30 V is potentially lethal (maximum allowed in High schools and College physics labs, in France)
So ALWAYS use an amp with a 3 wire cord, grounding the chassis and the metal parts on your guitar... Please update your vintage tube amps (discard the cloth woven wires and ignore the self proclaimed "tube gurus" opinions: it might save your life, at ultra low cost...)
In continental Europe, we have 220 to 240 V power outlets : it's not forgiving!
240 V /1000 ohms = 240 mA = a one way lane to BBQ heaven
240 V / 100 ohms = 2.4 A = the frying pan
great video as always... BS free speech, coming from someone who knows what he's talkin about
Thanks for your detailed analysis, Serge. Your advice is excellent and definitely worth knowing by all.
Aaaand now I'm shopping for new mic stands with rubber feet...Thanks, great job, Uncle Doug!
It won't help if the metal parts of the microphone or stand are of a different AC polarity than the strings on your guitar, AJ.
Good video Doug ! It'samazing how an old amp can shock you or not just by flipping that two prong plug. I'm a big fan of grounded plug.
Thanks, Bobby. I agree with you re the three-wire grounded cord, especially if you are going to set up your equipment with other equipment of unknown polarity and grounding. As my old granny used to say, "It's always better to be safe than sorry."
You might try plugging the laptop into one of the grounded outlets to see if that remedies the situation. If so, then by all means get the one, ungrounded, outlet replaced. We need you to stay healthy and "unshocked", Len !!! :))
excellent drawing😉
Thanks :)
Doug - always great work. You are very appreciated.
Just a couple of thoughts: The microphone is usually attached to the stand with a plastic or hard rubber clip. This would pretty much isolate the mic chassis ground from the stand. Also, many mic stands themselves have rubber feet to keep them off ground. In that case, touching the guitar strings to the mic stand won't do anything, other than charge the stand.
Thanks, Paul. Rubber feet or not, if the microphone and/or stand have/has a polarity opposite that of the guitar strings, a potential will exist.....as will a shock hazard. The potential between microphone and ground is immaterial. All that matters is whether, due to improper wiring and mixed polarity, a potential exists between any two pieces of equipment. This can be prevented by the proper installation of polarized, 3-wire, chassis-grounding power cords.
I'm glad you survived it, BT......240VAC will really get your attention. Although your experience was not amp related, I feel compelled to mention that when working on a live chassis, it's a good idea to keep one hand in your pocket....that way you can never accidentally complete a circuit from arm to arm (through your chest and heart) that might be fatal.
Someone else that works on amps told me that too. I have a Fender Champ 600 to fault find so will ensure I abide by that method. I'll probably also wear a nitrile glove on the other hand 👆. The amp gave up, it used to run rather hot for its mere 5W (output). Previous owner had someone install a modification kit consisting of an improved rectifier, DC heater supply and standby switch. I suspect they failed to follow the final part of the modification instructions (that I have obtained) that should check and adjust (resistors) to set the correct voltage to the tubes. So carefully checking that could be my starting point.
@@SaxJockey That sounds like a good place to start, SJ. Good luck with your project.
this is something that i have a great deal of experience with. while playing along with a very good guitarist and friend travis m. the guitars strings were just switched out on both our guitars we were in close confine jam space the rxcess weren't trimmed but left flayling about and as we walked near each other and zapp i received a shocking to my arm better than a gallon of coffee i laugh about it now but it is a very important part of band safety. thanks Uncle Doug and Rusty for making all that are watching aware
You're welcome, Tim. I worried about having an untrimmed string stab me in the eye, but never considered them to be a shock hazard.
Great video. Had a band mate get a shock off a mic stand once, and this is in the UK where everything should be ground wired. He played on against my advice, but thankfully survived!
It happens a lot, Alex, and hopefully the video explains why and how to avoid these shocking experiences.
+Giath Majstorovic I've never had any venue ask for proof that gear was PAT tested, and we've played a lot including some medium sized festivals etc. In any case this was the venue's gear so wouldn't have helped!
hey uncle doug - thanks for answering - i haven't had a look inside the amp yet, the shop owner told me he has taken the death cap out, or usually takes them out - might have forgotten it, will check. but the idea with a fuse makes a lot of sense, it wouldn't be worth risking the amps life or mine. the shop own / amp tech wrote me as well he'd liked check all over the amp again, to see if there are any leaks and will build in a fuse as well. should be save again then ;).
You may have saved my life by making this video...I have zapped my lips on mics many times...and shocked myself on my amp's chassis several times in the past...my amp is circa 80's point to point -100w with 3 prongs but I suspect I have a grounding issue...I am going to check things out with a volt meter as you suggest. Incidentally, I once saw a video of Hendrix rubbing his guitar against his mic stand...perhaps more as a precautionary, rather than artistic measure.
Bob Flint If the video prevents you from receiving a serious shock, Bob, then it truly served its purpose. You really need to investigate the cause of the shocks you have been receiving. Bear in mind that the fault may well be in equipment other than your own. If your amp and guitar strings are properly grounded, then you become grounded when you touch them, and electricity from any improperly wired equipment you come in contact with will try to pass through you to that ground. Jimi was checking to see if his (grounded) strings were attracting an electrical spark from the mic stand before he came in contact with it. It's a standard test, as mentioned in the video, and sort of a last resort. A little portable voltmeter can do a better job of assessing any potential between pieces of equipment and can save your life. Best of luck.
You're welcome, Philo. I hope it all made good sense.
I plugged my old guitar into a gen 1 Boss Katana amp and I got a HUGE shock... By how good it sounds!
That's the type of shock we can live with, William :)
Years ago my wife got tired of my incessant practice and so to keep the peace I took my Peavey Deuce 120 watt amp and my Fender guitar out in the back yard on a concrete slab and began my daily practice...for about 3 seconds until I got the living snot shocked out of me, I was wearing leather soled boots and using an extension cord, I turned on the amp and touched the strings and it lit me up! Good advice people! Of course I can walk out to my car and throw a one inch arc to the car door (this happens to me all the time , it's very annoying) Great video!! Thanks!
Thanks for confirming the hazards associated with electrical music gear, Jack. You really have to be careful.
Appreciate the video. Thank you. Years ago I worked in a radio station that the transmission mixing board had been there for 30 years and the metal chasis was hot and would shock you. Touch the faders all that and you were fine. For some goofy reason the station would never get it fixed and I was always nervous changing anything on it or walking near it. I wonder if its still there....
You're welcome, Chris. Nowadays, an employee would claim permanent injury from the shock and retire on his legal settlement.
I'm a little confused by the question, AR, but the word "potential" means a difference in electrical charge between two objects or locations. If a connection is made between them, then a current will flow from the one with too many electrons to the one with too few. If a potential exists between an amp chassis and ground, and if you touch both, an electric current will flow through you from the chassis to ground.
Thanks, F86. I just watched a video of his and couldn't resist. I probably should have included a cigarette on his lip too, just to make it more realistic, but the smoke might have made it look like he was being electrocuted ;)
Great tutorial Doug.
Another thing that frequently happens when playing in old houses, rentals, building's, etc.
Is that in past times,
to make "rentals", old houses, etc. To make an old two prong cloth wired house appear up to code, deceptive individuals will replace the old two prong outlet with a three prong to the old cloth two wire leads.
Therefore, still, no real earth ground, so to speak.
It's only there for looks!
Tip; If you don't have a small meter with you?
Carry a modern 3 prong outlet checker that you can purchase a quality model for under $10 at a good hardware store that will have indicator lights that will immediately inform you about the outlet wiring.
Or if your a band set up person for a small PA or whatever?
Go find the breaker box or fuse panel from days of old.
If you don't see modern grounded wires or even the breaker box properly grounded outside, which I have witnessed more than once. Skip that gig or go unplugged all the way around.
As Doug mentioned, some famous musicians have been electrocuted on stage and some have died when they touched the mic.
Great young talent, so sad.
Crucial video Doug, thanks.
Thanks so much for your helpful input, Amo.