i'm on a roll... the kgsshv

[Craig Sawyers]

They did say that the current likely drove his heart into fibrillation and that there was no one around to help as he was incapacitated possibly by the still connected meter. 10-100ma could do that correct?

Totally beyond credibility.

Experiment: I wired up a Fluke 8060A on ohms range with a Fluke 87V on micro-amps range. I could not get a reading on the 87V try as I might. The 8060A indicated a resistance in the mega-ohm range (1 to 10M), even pushing the tips into painful pointy contact with my fingers.

I then took a 9V battery, and wired it via the 87V to my tongue (the traditional old fogey way of testing a 9V battery by feeling the tingle. Welcome to my world.). The tongue is about as wet and electrically conductive as it gets. I measure 12uA from a 9V battery on the tip of my tongue with the connections separated by a few millimetres.

To get anything approaching the ten *milliamps* needed to give you heart problems would need you to stick a nail through the palm of each hand. I was not prepared to take the first steps in self crucifixion to test that out. But I could not get within three orders of magnitude of a problem current of that even on my tongue.

So let's move on to the *real* problem of keeping you all breathing when dealing with dangerous voltages like 500V or 1000V - where the potential gradient across the skin can punch through and set up a real kick-ass current flow from a grunty power supply like the kgsshv one.

[manaox2]

Glad you didn't kill yourself Craig.

[Dusty Chalk]

Well, there are 9V lantern batteries that can deliver a bit more current, but the story in the link explicitly states that it was whatever battery was in the multimeter, so...I don't know.

[kevin gilmore]

I've been testing 9 volt batteries the same way for over 40 years. Don't know where i learned that trick.

Its not the size of the battery, Its the voltage divided by the resistance of the load.

[luvdunhill]

Its not the size of the battery, Its the voltage divided by the resistance of the load.

That's not what she said.

[manaox2]

Nipple clamps to 9v is standard in some hobbies.

sent via Droid X

[MASantos]

Just add an Ipod!

Nipple clamps to 9v is standard in some hobbies.

sent via Droid X

[nikongod]

Nipple clamps to 9v is standard in some hobbies.

How else would you grid bias a tube with top caps?

[spritzer]

Neither do i, but i fake it real good.

Fake it, till' you make it...

[livewire]

The warnings about high voltage with significant amounts of energy storage are very real.

This power supply has more storage at more voltage than a heart defibrillator.

The story on the guy with the voltmeter is complete and utter bullshit. For one thing

the simpson 260, of which i have 2 brand new in the box uses a total of 1 x 1.5 volt D cell.

The older ones have 2 x 1.5 volt D cells. The maximum amount of current this meter can deliver

on the low ohms range is about 1 ma. This is not enough to kill no matter how hard

you try. On many of the DVM's however, there is a 9 volt battery, but once again these

work on a current source principle, and even on the low ohms range the maximum

current is 1 ma with a 1 volt maximum. 5 volt maximum on the diodes range.

The best rule on this is insulated shoes, and one hand behind your back at all times.

Safety glasses also a real good idea.

Do foam rubber flip-flops count as "insulated"? (j/k)

Seriously, I use a non-conductive floor mat at my workbench when dealing with the HV stuff.

The same kind that I use at work when tearing open 480vac electrical panels.

[kevin gilmore]

I would not be caught dead with a green checkered doily under my equipment!

I stay away from the 440 volt panels...

And i saw the new 14.4 KV panel that drives the transformer for my new building.

Stay away. Stay very far away.

[livewire]

14.4 KV? I just wear one of these and I laugh in the face of the plasma arc fireball that envelopes me.

Maybe include it on the KGSSHV BOM? (for us n00bs)

[ATTACH=CONFIG]3927[/ATTACH]

[livewire]

Didnt mean to kill the thread....

I'm thinking about going with a single box on this build.

Black with custom cocobolo side panels. (ala Hammond)

Kind of big though, I think it will all fit inside.

Par Metal #20-16164B.

Thoughts?

[ATTACH=CONFIG]3953[/ATTACH]

[ujamerstand]

It won't fit. Imagine this as the chassis:

You won't be able to fit the power supply in there.

[livewire]

I dont have any boards in hand, but resizing the overlay jpegs using a heatsink

as a size reference, I get approx 9" X 7.5" for the psu board,

and 8.25" X 6.25" for each of the two amp boards.

Theoretically, I get this as a rough mock-up:

[ATTACH=CONFIG]3955[/ATTACH]

It's going to be a fairly tight fit.

Also due to the 4" height of the enclosure, I could slightly overlap boards if need be.

FWIW, the wood side panels will be slotted in the middle to help with ventilation.

[kevin gilmore]

Yes its going to be very tight in that case. Also remember you need input and output jacks, and

an input power jack. If you push the power supply all the way to the transformer, move the

transformer up a bit, use the thinnest ac input jack you can find, you should have enough

room on the other side for xlr jacks.

[digger945]

Why not just go with a chassis that has enough room to start with. Par Metal has many different sizes to choose from, and even "Create a Size" for those applications where "that extra quarter inch can make a world of difference."

I didn't know that Par Metal now offers heatsinks. No price, but they do offer to cut to your specifications. No, I'm not suggesting another board layout change:)

[ujamerstand]

Huh. I stand corrected. But that is a tight fit...

I've seen people agonizing over par-metal's customization services though, not sure if their create-a-size service would be any different. But I would be interested in their heatsinks if a "balls-to-the-walls" version for kgsshv is released.

[livewire]

@digger945,

Yeah, I saw the "create a size" thing.

I surmise by doing that, it will almost double the cost of the case.

I'm trying to do this build on a shoestring budget,

the 16 X 16 X 4 case that i'm looking at, costs $57 + s&h, unfinished.

I will call Par-Metal tomorrow to find out what a custom 16 X 17 X 3 case will cost.

I do prefer a lower height, but not if I have to pay through the nose for it.

[kevin gilmore]

Standard power supply caps are 50mm... So if you pick the ones in stock now that are 63mm

then it isn't going to fit into a 3 inch high case. (vertically)

[Kerry]

For fun I've been playing with the HV power supply. I've modified it to work with the Blue Hawaii at +/-400V. I'm posting here since I first started playing with it in thread. Now that I understand the design, I think it's really very slick.

Here's the rough schematic and board layout. The board is 12" wide and designed with the heat producing sand to sit on the chassis' heatsinks.

images removed by request of Kerry

Edited November 24, 2010 by deepak
request to remove images

[luvdunhill]

Kevin and Birgir:

I'm assuming this design is something that you feel comfortable seeing the light of day? I mean, wasn't the active battery circuit the one piece of the circuit that the designer felt was novel? I know you were protecting some parts of the T2 design in honor of the designer and just wasn't sure if this was one of them.

[Kerry]

I thought that this was published already. I don't have the ability to take this down anymore.

[livewire]

Standard power supply caps are 50mm... So if you pick the ones in stock now that are 63mm

then it isn't going to fit into a 3 inch high case. (vertically)

I picked up the 2" high psu caps a while back.

63mm = 2.48", so it is possible in a three inch tall enclosure, depending on inside height.

Instead of stand-offs under the pcb, a thin (~.062") insulating sheet

of high dielectric plastic could be used.

[deepak]

I thought that this was published already. I don't have the ability to take this down anymore.

Kerry if you (or anyone else) wants it removed it can be done