I choose........E) None of the above!
Most defibrillators go to 400 Joules. The two common caps are 15uF at 7500 volts or 30uF at 4000 volts. The filter cap in the picture below came from a defib unit. I had a lot of fun "testing" stuff with a defib unit. Note: Never connect a defib across a bananna and push the test button unless you like cleaning goo off of the ceiling!
Instinct probably would have forced me to put the wrench or at least a long screwdriver across the cap terminals. After exploding the 260, I went home. Again, instinct. I don't like playing with electricity when tired or otherwise impared. Older now, and able to learn from my earlier stupidity, I turn off all dangerous electricity at 10PM, and think twice before doing something potentially hazardous. Really stupid experiments are behind a Lexan shield! See picture. Complete story here:
The 833A SE Amp Prototype
Mine lasted from ages 16 to 37. Coincidentally that time period was when I made most of my guitar amps including the biggest monster I ever made. It made an unknown amount of power. The more speakers (lower load impedance) you connected the louder it got. I saw over 1000 watts at 2 ohms. That was a lot of power for 1971.
Somewhere in the late 60's I was helping a friends band set up for an outdoor concert at a strip mall. It was a typical Miami summer day, 90+ degrees with 99% humidity. 5 minutes outside and you are wet with sweat. The mall people had provided one extension cord to power the whole band. My friends Acoustic 260 guitar amp was not liking the power at all. With one hand on the grounded guitar, he decided to check the temperature of the output transistors with the other hand. Launching the F-bomb into a working microphone might be acceptable today, but it didn't go over two well then. The concert was cancelled!
Attachments
Now he tells me !!!. where were you 20 odd years ago when I stuck a conductive screw driver under that rubber cap on a colour tv, about 60,000 volts stored in there, blew me across the room an almost caved my head in on the wall (no dry wall here it was concrete breaze block.
but i did learn a thing or three.Now that you mention it, I used to have a bunch of truly non-conductive tools for working on a live TV. Doubt I could even find them anymore. Don't want to become a human hipot tester of the insulation on my needle-nose plier handles. And just getting back into tubes lately, I do appreciate the reminders.
Shortly after high school (1973) I took a part-time job at a local electronics repair shop. I was working on a solid state stereo console which had a dead channel. I found several dead transistors in the output section, and after replacing them turned the amp on to check voltages and such. The amp worked for a few seconds and then I heard an odd crackling sound. I started to get a little closer to the PC board to figure out where the sound was coming from when a loud pop, followed by a capacitor shell hitting the ceiling scared the crap out of me. There was nothing left of the electrolytic cap but a trail of paper and foil.
Was checking an old Baldwin organ amp once (PP 6L6's) that was still in the organ in my garage when I first started messing with tubes. There wasn't much light so I clipped my leads on my multimeter to the secondary of the PT to see what it was putting out loaded. Grabbed a throw light with the metal shroud on it to get a better look at the meter display and had my index finger up against the metal shroud in my right hand. Touched the chassis with my left to move it a bit and WHAM...460VDC right across my chest. Didn't even think about the light shroud being grounded. I sat down (I was kneeling down at the time anyway) in the middle of the garage floor for about 45 minutes before I could get my heart to settle down enough to stand back up. I couldn't even talk.
When i was about 16 (about 1974) i learned a valuable lesson about octal valve connections. Up till then i thought all top caps of octal valves were the grid connection. Iused to stick my finger on the top cap to hear the blurt out of the loudspeaker untill i came across an amp with 807 output valves. I stuck my finger on the driver valve top caps to get the usual blurt. Then i stuck my finger on the top cap of the 807. Knocked the living #### out of me. I sat on the ground for several minutes before my feet would work again. Lesson learnt and not forgotten!
mmm, nice stories.
As a very young toddler (younger than the story below) I apparently grabbed one of my dads mains plugs and it had a wire hanging out the end of it maybe 2-3 inches long, I apparently plugged it into the wall and turned it on and watched for a few good seconds while it sparked until someone turned it off, my dad sure did learn his lesson that day, after that he never had mains cables hanging around waiting to be plugged in, not even until I was 15!!
As a toddler (bit older) I once turned up the volume on my dads Teac home theater system, the puported wattage was about 40w RMS into a set of floor standing 3-ways, I grabbed the knob, turned it to 11 and turned on the amp! and grabbed my ears and started crying until someone came and turned it off for me, lol.
As a teenager at about 13 yo I disassembled a HUUUGE photocopier and pulled out the geared drive motor for it, it was a huge thing, permanent magnet, which I now know means that it produces power when spun! and as I was fiddling around with it I asked my friend to hold one of the leads for it up to a multimeter and I spun it because I wanted to show him how many volts it put out, sure enough I was holding the other multimeter lead and that and my feet which were holding it down as it got spun completed the circuit.
I would guess that it put about 50-80v across my chest, at least thats what I remember the multimeter saying.
As a very young toddler (younger than the story below) I apparently grabbed one of my dads mains plugs and it had a wire hanging out the end of it maybe 2-3 inches long, I apparently plugged it into the wall and turned it on and watched for a few good seconds while it sparked until someone turned it off, my dad sure did learn his lesson that day, after that he never had mains cables hanging around waiting to be plugged in, not even until I was 15!!
As a toddler (bit older) I once turned up the volume on my dads Teac home theater system, the puported wattage was about 40w RMS into a set of floor standing 3-ways, I grabbed the knob, turned it to 11 and turned on the amp! and grabbed my ears and started crying until someone came and turned it off for me, lol.
As a teenager at about 13 yo I disassembled a HUUUGE photocopier and pulled out the geared drive motor for it, it was a huge thing, permanent magnet, which I now know means that it produces power when spun! and as I was fiddling around with it I asked my friend to hold one of the leads for it up to a multimeter and I spun it because I wanted to show him how many volts it put out, sure enough I was holding the other multimeter lead and that and my feet which were holding it down as it got spun completed the circuit.
I would guess that it put about 50-80v across my chest, at least thats what I remember the multimeter saying.
I was always told that it was AC that was the one that didn't let you go, or rather that you didn't let it go because your muscles will flex and grip onto whatever you were holding.
In either case its a good idea to not come into contact with either type, no matter what the voltage and no matter the current....
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I know when i got lit up bad I couldn't move at all what it was I left my damn delay pedal hooked up in the loop and I reached across with my left arm because I forgot to turn it off and **** grabbed me. being half drunk reaching across an open chassis like that yeah I know real smart right? lol
I went to a technical high school in the late 60's. I was in a 3 year long electronics program. Being funded by the Miami Dade county public shcool system meant there was no budget and everything was old and out of date. We played with tubes! This is where I learned how to "make em glow"!
Much of our equipment and "scrap" was donated by local corporations and the Homestead Air Force Base. The donated scrap was available for the students to experiment on and if we built anything useful, it was ours to take home. The AFB had donated about 20 Stromberg Carlson PA amps that used 4 X 6L6GB's for output tubes. I had claimed two for building my stereo system. The AFB had also donated several hundred NIB metal 6L6's, so those went into the Strombergs.
Our workbenches were metal, and grounded through the electrical conduit that supplied each bench. Some benches had isolation transformers, but many did not. The transformer equipped benches were in the front of the class and reserved for the less experienced students that followed the lesson curriculum. The first hour of each 3 hour class was lecture and the last 2 hours was lab time. I did not do the simple "build an amplifier stage and measure it" labs, since I already knew this stuff. In fact I didn't do many of the lectures either, since I could ace the tests. There were 2 of us that just built or fixed stuff in the back of the lab.....on one of the grounded benches.
I got the Strombergs working and brought in my big speakers and a turntable for "testing" and one day we all learned several important lessons:
1) The metal case on a 6L6 and most other metal tubes is connected to pin 1.
2) Pin one on the tube in the back of the Stromberg amp is used as a tie point for the screen supply voltage.
3) The Steppenwolf Second album has a shiney foil cover over the cardboard. It CONDUCTS electricity quite well!
4) The album cover flies quite well Frisbee style when you accidentally touch it to the 6L6 tube while leaning against the metal bench rail.
Much of our equipment and "scrap" was donated by local corporations and the Homestead Air Force Base. The donated scrap was available for the students to experiment on and if we built anything useful, it was ours to take home. The AFB had donated about 20 Stromberg Carlson PA amps that used 4 X 6L6GB's for output tubes. I had claimed two for building my stereo system. The AFB had also donated several hundred NIB metal 6L6's, so those went into the Strombergs.
Our workbenches were metal, and grounded through the electrical conduit that supplied each bench. Some benches had isolation transformers, but many did not. The transformer equipped benches were in the front of the class and reserved for the less experienced students that followed the lesson curriculum. The first hour of each 3 hour class was lecture and the last 2 hours was lab time. I did not do the simple "build an amplifier stage and measure it" labs, since I already knew this stuff. In fact I didn't do many of the lectures either, since I could ace the tests. There were 2 of us that just built or fixed stuff in the back of the lab.....on one of the grounded benches.
I got the Strombergs working and brought in my big speakers and a turntable for "testing" and one day we all learned several important lessons:
1) The metal case on a 6L6 and most other metal tubes is connected to pin 1.
2) Pin one on the tube in the back of the Stromberg amp is used as a tie point for the screen supply voltage.
3) The Steppenwolf Second album has a shiney foil cover over the cardboard. It CONDUCTS electricity quite well!
4) The album cover flies quite well Frisbee style when you accidentally touch it to the 6L6 tube while leaning against the metal bench rail.
I got zipped the other day badly. Getting tired of this. I was intoxicated - condition sine qua non - and playing guitar and doing mods witth the amp open and ready to kill. Well, it did not kill me but it sure tried. The flow went through my chest: had one hand holding the guitar (touching the strings) and the other hand was doing silly things. The first thought after a shock is always the same: my God that was fast! I can't believe the SPEED. It always strikes me how fast it goes, I mean it's faster than anything I have ever experienced. Anyway, the intensity is pretty much the same with 400 volts. A 250 volts shock is a third less intense (of course I'm talking about my own experiences).
When I want to school Industrial technology etc lol I was in a class with about 20 people and they had 1 of those like Electrical trainer machines with an assortment of relays, transformers and light bulbs etc lol just to experiment and learn and test stuff etc well we charge up caps like the little 6mm bastards and hide behind the machine and wait for that unsuspecting person to walk by or in front of it lol you get the idea lol
When working on some silverface Fender combo I put the chassis back in the cabinet, turned on, but realised that for some reason it was not ready yet. I wanted to go the fast way, and with the amp still powered up I reached under the chassis to pull it out by a few centimeters. Should have been aware of the fact that the cap cover had been lying on the desk the whole time.
I love these stories- thanks.
I started working on tube circuits when I was 11 or 12. (Built my first "real" amp at 15.) My buddie's dad was a real old school ham radio guy and he showed me how to work safely on circuits. He taught me to use a wire with alligator clips and series resistor to discharge caps (hook up the ground first!). So I never got a shock working on electronic circuits (yet).
But I have gotten a couple of whoppers. I was installing new electrical service once and I managed to get one of my clumsy hands across
both hots (really stupid). I got a very bad shock and was thrown down on the concrete. I was dizzy for about 15 minutes and went back to work. Another time I shorted both hot wires with a large vice grips. The whole top jaw was vaporised and I was subject to a blinding (literally) flash of light. My eyesight recovered in about a half an hour.
I started working on tube circuits when I was 11 or 12. (Built my first "real" amp at 15.) My buddie's dad was a real old school ham radio guy and he showed me how to work safely on circuits. He taught me to use a wire with alligator clips and series resistor to discharge caps (hook up the ground first!). So I never got a shock working on electronic circuits (yet).
But I have gotten a couple of whoppers. I was installing new electrical service once and I managed to get one of my clumsy hands across
both hots (really stupid). I got a very bad shock and was thrown down on the concrete. I was dizzy for about 15 minutes and went back to work. Another time I shorted both hot wires with a large vice grips. The whole top jaw was vaporised and I was subject to a blinding (literally) flash of light. My eyesight recovered in about a half an hour.
For my second amplifier build, I purchased 8 10,000uF caps. They were the kind with threaded holes on top to bolt a ring or spade terminal. They also had a threaded shaft on the bottom, which, I assumed, was for mounting to a chassis. I built the power supply on a wooden block first, and everything went well. But when I transferred it to an aluminum chassis, putting the threaded shafts through holes drilled in the bottom - POW! Every time I turned it on I got an explosive flash, and blown fuses. It was driving me crazy. I checked and checked and tested for shorts and couldn't find anything. Finally, I flipped the amp over, and saw the chassis around the mounting holes was charred black. It turns out the shaft on the bottom of the caps was not for mounting them, but was actually a second lead, connected directly to one of the leads on the top of the cap. So I was creating a short from one of the rails to ground. I still can't imagine why anyone would make such a ridiculous design. I cut off the shafts, put a bunch of electrical tape over the bottom of the caps and mounted them with rings.
So I didn't actually light myself up, but scorched my amplifier chassis several times.
So I didn't actually light myself up, but scorched my amplifier chassis several times.
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