Safety Practices, General and Ultra-High Voltage

[angsuman]

hmm could you please elaborate. This is my plan, I have 10 47uf 250v capacitors. The resistors are 220k.

[SY]

A few things:

First, you probably don't want the first filter cap to be all that huge. Big input cap = high ripple currents = bad juju. 47u (four in series parallel) is more than adequate in that spot. Save the others for use downstream.

Second, you only need to have one set of resistors to balance the voltage. All of the "middle" junctions are at the same potential so can be connected together. That will simplify things greatly.

Third, the equalizing resistor values aren't too critical. 100K/2W will be fine.

Fourth, try to use high temperature rated caps.

[angsuman]

Thanks that makes far more sense.

[chrispenycate]

Ultra high voltages? Haven't worked with those for a while.
Still, I'm rebuilding a sixties guitar amp for a friend- tubes, of course (well, valves actually, since it's English, and so is he, and am I for that matter) and am enjoying working with properly sized components on tag board.
I'm one of the survivors of almost all the stupidities mentioned in previous posts (well, apart from the Van de Graf generator - I wonder where I could find…) and they're probably not going to get me before I reach sixty.
Safety? Silly things. If,like me, you find your teeth the best wire strippers, stop. Sooner or later the other end of a a wire will be connected, and it leaves a horrible taste in your mouth.
Don't sweat, or at least get rid of it while working. Dry skin can survive things sweaty skin would transmit straight into vunerable portions. And don't bleed into the components.
Don't try and mend an amp backstage; Light in quantity and open space are essential, not to mention the relative reliability of the power lines.
Keep tools clean; having insulating sleeves on your cutter handles doesn't do any good if they're covered with oil, swarf and sweat.
I had alove affair with 807s, for a while, and they are more or less guaranteed to go off RF unstable from time to time. It's amazing what can get charged up when that happens (usually just tingles; but knowing the volts kicking around, you tend to get very sensitive ti tingles, and jump. Don't.)
Always unplug things, don't just turn them off.
Remember the Leyden jar; a big output tube can hold quite a lot of charge, even when unplugged from the chassis. When it bites you, don't drop it.
Never agree to repair the power supply of a gas laser with multiple, water cooled, totem pole TO3 transistors.
Know your circuit, and what every point does; it might not prevent you from getting shocks, but at least you'll be able to judge how much of a shock you've just had.
Switch mode power supplies are the work of the devil; assume they're out to get you.

[Jmmlc]

Hello,

In the links at the end of that message you'll see a 1kilowatt amplifer operating under 5000 volts.

THis ampliifer won the "white lamp shout out" during the last "European Triode Festival 2007" in Biezenmortel (The Netherlands)

http://www.audioasylum.com/audio/tub...20/201989.html

Best regards from Paris.

Jean-Michel Le Cléac'h

[richwalters]

Originally posted by chrispenycate

Switch mode power supplies are the work of the devil; assume they're out to get you.

No! there's nothing wrong with switchmode power supplies, it's the work of the devil engineer at fault. I've been using smps for tube applications for 35 years.....luv'em.

richj

[patch]

Shocks....I want to think in terms of a hospital operating room.

1. Insulate the hands with gloves.

2. See the work, light the workspace. Brilliant light, shielded from the eyes. I like a photographic modeling lamp with barn doors and a cool-running bulb.

3. Organize. Hand tools (and parts) arranged on a shelf under the bench until needed, or well off to the side. Avoid placing them where you will have to reach over the work. Pick the tool for the immediate task, then put it back in place.

4. When the power is on, slow way-waaaay down (I think to line up my movements with the sound of Hal's voice at the end in 2001 Space Odyssey).

patch

[Wavebourn]

Originally posted by richwalters
It's well known in agriculture, the hv electric fence is also used in cow stalls to keep rowdy heads and horns down.
richj

In South Africa they are installed on walls to protect properties from intruders. Living in Ferndale (Randburg, Gauteng, one of northern suburbs of Joburg) in 1999 I made one custom system using horizontal output transformers from computer monitors and with photo cameras around (35 mm film, video cameras were too expensive then), so each discharge caused a camera shot and e-mail to my address with time stamp and information of the place where it happened.

...as the result, I always knew when and where to trim a bush.

Once when a rain started after long dry winter I had to shut it down because some salt on insulators shorted the path. That night was stole n a huge battery from landlord's tractor... That night many yards were robbed. Illegal imigrants could not get jobs then even if they found some because they had to go back to motherlands and obtain work permits there that was impossible for them, so the single option to survive for them was to rob or steal.

[DMoe]

Always use HV gloves, I do with anything that is dealing with an electrical current...they have saved me a many of times.

[audiotore]

First post on the forum so, hi.

I'm at the age where I need to think about setting myself up with some kind of trade and I was thinking about exploring the possibility of pursuing a career in being a studio tech but after reading this thread I'm seriously having second thoughts. I guess I should think about the thousands of people who work at this stuff every day and I guess most of them make it to the next day, alive. But seriously, can someone offer some words of assurance... please?