Have You Ever Been Shocked Working On An Amp

[jelle]

Hi Guys,

I have been stupid enough once to try to replace filter caps right after I had played them. ZZZZZAP!


I learned from this

jelle

[paulster]

Mercifully I haven't, but I have seen the effect first hand.

One of my pals got bitten by an amp and jumped back across the room. While he was sitting there waiting to regain his senses he failed to notice the soldering iron he was now leaning against after his flailing around had knocked if off the bench he'd landed against.

Cue him suddenly lurching forward across the room again with a burn in his back this time!

Either incident could have been really nasty but it played out like a comedy sketch.

[drhulsey]

...My whole arm tingled for about 2 days.

This was due to the effect on the function of the nerves. They were firing involuntarily.
With the mains voltage we usually deal with, death is caused by the heart stopping- cardiac standstill. This is an electrical disturbance and not due to damage to the heart muscle. It also requires that the current travel ACROSS the heart, e.g., from hand to hand. In Dart's case, getting shocked on one hand would not have affected his heart rhythm (although it may have affected his speech pattern and vocabulary ). The same thing happens with high voltage electrical injury, although an entry point near the heart can cause muscle damage.
If you see a person collapse after an electrical injury, and ONCE THE VICTIM IS NO LONGER IN CONTACT WITH THE ELECTRICAL SOURCE; repeat: Once the victim is no longer in contact with the electrical source, ALWAYS attempt CPR on electrocution victims without pulse/respiration. Resuscitation is frequently successful since this is a heart rhythm problem. Even in high voltage victims where there may be a lot of damage to the entry and exit areas, do CPR if there is no heart beat/respiratory activity.
I know everyone on this forum has heard the safe practices lecture, but I thought some might not be aware of the success of CPR in these injuries.

And to answer Jelle's question: Not yet

[nickt]

I had 240V mains thru my thumb many years ago while working on an electronic balance. Burned black between the in and out points. The shock was as a result of being distracted by my manager while I was fault finding with the power on.

Ever since I'm very careful with all electricals and stop, turn off and unplug when spoken to.

YMMV

[islandamp]

I once shoved a 6550 in holding the metal band of the tube. Unknown to me the key on the tube was broken and I shoved the grounded pin into the b+ and took freshley charged cap voltage into my hand. I squeezed the tube so hard the glass broke and cut me twoplaces and the rest of the tube shot up to the ceiling. If I ever come across a tube with a broken key again, I,ll trash it.

[Structo]

Whoa!
That sounds nasty!

[Bob-I]

Been there, done that, got a T shirt... and the scars.

Worst one for me was in the 70's. I had an SF Twin Reverb that I'd put a 3 pronged plug on. The bar we were playing in didn't have 3 pronged plugs so I used an adapter.

Test the amp, fine. Test the PA, fine. Step up to the mike for the first song...... next thing I knew the paramedics were hovering over me. Apparently the 110V went from my mouth to my left hand. Knocked me out but the show must go on. Finished the gig.

[BBQLS1]

Yes, I once touched the leads on an open OT. I learned my lesson.

[mumford]

I once installed a filter cap in an amp, then for whatever reason took it back out without firing the amp up. I was literally shocked to discover that it had charged up somewhat-- the lead on one end burned a hole into my finger.

[krash]

Well I was a product safety engineer for about 5 years doing mostly NEBS, Telecom circuit testing and design, lightning tests, etc. You get pretty good about avoiding electrical shocks when you are working around 10KV impulse generators and power line fault simulators that will deliver 600VAC with 1% regulation at 66A of current by design.

But still I managed to get zapped by the B+ from an undrained filter cap while working on this Deluxe Reverb that is on my bench for a customer. I am familiar enough with my own layouts to keep my hands off of the stuff with high voltages, but not so much with an old BF DR. That's what I get for taking on charity mod work.

[drhulsey]

... next thing I knew the paramedics were hovering over me...

That's just the scenario I was thinking of when I mentioned the use of CPR above. If you were breathing and had a pulse, it probably affected your brain activity, causing loss of consciousness. Had you grabbed the mic with your right hand and the guitar neck with the other, it could have affected your heart
It takes a REAL MAN to be shocked to unconsciousness and the finish the gig
I'm impressed

[LOUDthud]

Back in the days of two wire mains in the US we used to leave the strings long on the tuning pegs and touch them to the microphone before attempting to talk or sing. If you saw sparks, you had to reverse the ground on your amp or the PA.

[dartanion]

Hey Dr. H,

Nice little lecture on the heart. I know full well about safety around a tube amp and about how the heart works. I spent 4 years working for Medtronic working in heart failure research then in pacing clinical. I did mostly IT work, but they put me through enough coursework for MS in physiology/cardiology. I worked with some very big names in industry there and was surrounded by an unbelievable assembly of brain power on all fronts.

One of the coolest things I worked on there was rate response algorithms and got to test devices on myself and other employees. We'd basically shave a section on upper left chest, lightly sand the skin, and tape on a test device and a digital holter then run/walk on a treadmill, ride a bike, run up stairs, or whatever! We were developing different RR modes at the time. I aways wanted to develop a SEX mode so we could claim this in our marketing materials:lol: I also learned to spell tachyarryhthmia:shock:

I have also worked with many of the big pharma companies and a bunch of biotechs. My current client is a CRO, which is like a small biotech with no funding.

[Structo]

I've read that it can take as little as 500 ma to stop your heart if you get the current across the chest. Don't know if that is true and probably also depends on the voltage pushing it.
One time in the early 70's in electronics shop at high school I was working on a circuit for flashing neon bulbs and the supply was 500 vDC.
I was sitting on a bar stool type chair at the bench when I touched something I shouldn't have and it catapulted me backwards flat on my back.
Luckily I only got the charge in one hand and wasn't injured but the next class was a lecture on the dangers of electrocution and it's effects on the heart and muscles.
Thinking back I'm a bit surprised we were allowed to work with voltages that high but it was early on for semiconductor experiments so we were still dealing with B+ type voltages.
Of course we had been taught proper safety procedures but my little incident prompted a more in depth discussion......

[Structo]

I also believe that working around high voltage is kind of like riding motorcycles.
There are those that have been down and those that will go down eventually.
The guys that say, nope, never happened and it will never happen to me are the ones that you read about in the paper later on.
Maybe a poor analogy but, it came to mind.
I'm surprised that there are 12 that voted that they have never been bit by electrons.

I remember watching a video of Gerald Weber teaching something about amps, probably setting the bias or something.
He got zapped and tried to go on like nothing happened then said, remember to be careful around lethal voltages.