safety tips

hi there
been lurking around here for while learning a lot of stuff. you guys are a great inspiration to me and my diy starts soon!

there are a few projects i'm interested in and i'll take jacobs advice and start with something simpler and safer like the gssl... but i'd like to move on to the valve circuits in time and i'm aware there are more safety issues.

does anyone have any advice on where to find safety tips for this kind of work? good sites or books... i suppose a meta is probably asking too much!

cheers for any ideas
tim-burns

Good grounding for your safety
and then worry about the audio

I think bleeder resistors are good for both prototypes and production units
...
resistors on the larger power supply caps that will store high volts even after you have turned the unit off ... for quite a long time
so the bleeder resistors will drain those caps to make it safe to touch ... not imediately but a few minutes later

Good wire colour coding for the various jobs will help you know how to handle cables and termination posts and lugs
I think we had a colour coding table at one stage

Have many of you guys have earth leakage breakers in the work shop ??

just get in there and mix it up.
it's a Pavlov's Dog thing.
You will soon learn where the rattlers of the chassis lurk.
If your DIY leads to a job in electronics, you will need to learn how to move about a hot chassis at an economically viable speed.
shortcuts will be taken.

If you want to see something scary, follow an electrician around for a day.

I would:

rate the hazzards as they appear on the schematic.
get a red hi lighter and mark the "max danger-I will fry like bacon if I touch this" zone-
this would be the mains area

then use blue for high voltgage, but filtered dc.
this is the area where you might get zapped, but if it's 300 or less dc, like 99 percent of the stuff around here, it will not hurt that bad.

then, locate the above on the chassis itself, and learn to use caution around it when hooking up leads and stuff.

anyway, tha zap schedule goes like this:



year one - 10 zaps, two real good ones, one requiring hospitilization, in which you recounted 6 past lives-usually ocurring durring the first week of DIY.
year two - 5 zaps, one seroius
years 3 to 10 - 3 bad zaps
years 10- to 20 - no bad zaps, but a lot of small ones
years 20 to 40 - many zaps but too brain dead from zaps to notice.
:razz:

really though, there is no great danger in DIY audio.
nothing different from any other aspect of your life that requires common sense, like don't take the toaster with you to the shower you when your late for work.

the main people who have to worry about elctrical DIY hazzerds are our mutatant freak cousins, the Ham radio operators. My brother used to be one. A transmitter chassis will kill you in a second.

My one and only saftey rule which I follow religously:

Unplug the chassis at the wall. Do not use the power switch.
Thats it.
Have fun!

this is a good start! thanks guys!

particularly like the zap schedule... i'll keep you updated cj! i had a lucky escape as a kid trying to melt an old bullet casing on an electric bar heater... managed to skip the darwinian selection process there...

the earth breaker sounds pretty useful tho! cheers kev

T

I was directed to this post recently when asking about mains wiring:

http://www.groupdiy.com/index.php?topic=44699&highlight=electrical+safety+concerned#44699

Very helpful stuff.

Cheers

Nick

Oh man, now i wanna make some valve stuff too!!!

I'm actually trying to break a diy habbit here, not increase it!! :wink:

Something "simpler" like the GSSL????

I thought this was one of the more complex projects.

If you want truly simple (but still very useful) start with something like this:

http://www.jensentransformers.com/as/as017.pdf

It's easy to build and actually sounds quite nice, particularly with good iron. You can use any number of quality input transformer choices from Jensen, Cinemag, Sowter, Lundahl, etc...

This was the first preamp I ever built, and it sounded great... that is, until I set the powered board down on a metal surface!!!



See also Kev's F110 or Joe Malone's IC Neve schematics. These are all good circuits that are simple, easy, and inexpensive to build (except for the iron, of course).

FWIW, Jakob's SSL clone was my second official DIY project. I even developed the board myself!

I only had to locate and break FOUR shorts before I got the thing working right.

I learned a lot, though....

:thumb:

JC

Keep one hand in your pocket when probing HV circuits. This will avoid currents passing through the heart and disrupting the rhythm---currents in the roughly 10mA to 100mA range are the most dangerous, until you get to the parboiling levels like the kid who died after a few days from being cooked by a 287kV line. He wasn't dead instantly but probably would have been better off if he was. He and his friend were practicing rappelling off of a HV line tower, definite Darwin Award material.

HV will cause huge muscle contractions and you are as likely to get hurt as a consequence of being thrown about as from the shock, so arrange things for a reasonably soft landing if you can. And have someone check on you periodically. If you can have gravity work in your favor so that you tend to fall away from the device you are probing when paralyzed, all the better.

Wear insulating shoes on a nonconductive mat, and don't work when you are sweating profusely---it makes for much higher skin conductivity.

[quote author="bcarso"]HV will cause huge muscle contractions and you are as likely to get hurt as a consequence of being thrown about as from the shock, so arrange things for a reasonably soft landing if you can. And have someone check on you periodically. If you can have gravity work in your favor so that you tend to fall away from the device you are probing when paralyzed, all the better.[/quote]

Wow. I must say that is some of the more graphic and morbid advice I've seen in awhile. I don't know why, but I found myself laughing out loud while reading it.

Don't get me wrong, it's good stuff, and accurate (as far as I can tell.... knock on wood), but it just seems so surreal and sobering somehow.

:shock:

JC

so the bleeder resistors will drain those caps to make it safe to touch

Click to expand...

I discharge with a grounded "Come to Jesus" stick across all the caps anyway. Don't trust the bleeders.

[quote author="rascalseven"]
Wow. I must say that is some of the more graphic and morbid advice I've seen in awhile. I don't know why, but I found myself laughing out loud while reading it.

Don't get me wrong, it's good stuff, and accurate (as far as I can tell.... knock on wood), but it just seems so surreal and sobering somehow.

:shock:

JC[/quote]

My no-fun-at-all father, who had been a ham, would not let me build an rf plasma torch when I was in my early teens. He had had a few near-death shocks, and he knew I would get careless and probably kill myself.

So I turned to chemistry MUAHAHAHA.

Then after blowing a hole in my leg, I managed to dislocate my left arm and also break it, just doing a little roughhousing.

Then I finally straightened out, and turned to drugs (hysterical laughter).

But I survived all of that and managed not to be all that much the worse for wear, mainly because I loved music and electronics and got far more joy out of them than most anything else. As they say, love what you do and you'll never work a day in your life.

larrchild!
it's official! how many zaps before i'm thrown out? and what the hell is a come to jesus stick? it sounds like something my RE teacher used to use on me for talking in class... i'm serious i'd love to know... please explain.
T

Tim - I had an old bullet casing experience as well
Somebody rigged up my bed at boarding school to explode a small detonator when I ripped open the covers..
Anyway...
First project - build a PSU - get one of Joes PSU boards
I hid under the table when I switched my first PSU on (abotu 12 months ago - a home etched one)

Second project - Green Pre
The SSL compressor has a lot of stuffing in there - with tight spaces if you have bought the wrong cap sizes - and the THATs are not cheap

Have fun..

cheers mate!

I actually use a small perforated steel blast shield when I plug in my PSU for the first time...

[quote author="northsiderap"]I actually use a small perforated steel blast shield when I plug in my PSU for the first time...[/quote]

LOL! I use a very long extention cord that's plugged into a GPO nowhere near any PSU, toroid or PCB :green:

[quote author="BladeSG"]
[LOL! I use a very long extention cord that's plugged into a GPO nowhere near any PSU, toroid or PCB :green:[/quote]
Thats one hell of a way to piss off your postman

A Reader in London asks:

larrchild!
it's official! how many zaps before i'm thrown out? and what the hell is a come to jesus stick? it sounds like something my RE teacher used to use on me for talking in class... i'm serious i'd love to know... please explain.
T

Click to expand...

Just my CB radio slang creeeping in to haunt me. I meant an insulated screwdriver attached to a grounded clip lead. wait a few seconds after powering down, and go from cap to cap discharging them all to ground.

When changing a 4CX20000 FM transmitter tube, each cabinet door, when opened, has a grounded discharge stick on a coil cord in the corner that one uses to discharge everything before servicing.

You are never thrown out of the Safety Club, you just become a non-active member=)

cheers larr
i figured it must be someting like that!

Thats one hell of a way to piss off your postman

Click to expand...

i'm sure he didn't mean General Post Office... although now i think about it they could do with some heat under their asses... 'first' class post hits me at about 12pm...

[quote author="tim-burns"]cheers larr
i figured it must be someting like that!

Thats one hell of a way to piss off your postman

Click to expand...

i'm sure he didn't mean General Post Office... although now i think about it they could do with some heat under their asses... 'first' class post hits me at about 12pm...[/quote]

It would be funny! I meant General Purpose Outlet or power point. I switch it on at the power point so I'm not going to be near any potential explosions, sparks or smoke.