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Registered Member #105
Joined: Thu Feb 09 2006, 08:54PM
Location:
Posts: 408
Well, in order to make a tube coil, you must have a tube with at least three elements- the plate, grid, and cathode- this is only a rectifier tube, which is basicly a diode. So, if you need a diode in your VTTC, this could be used as a part of it But as the main driving tube, you'll have to do a bit more searching. VTTCs are a lot of fun to build though, so keep lookin for something suitable!
Registered Member #56
Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445
You could use it as a part of a voltage doubler (level shifter like out of a microwave) although with only 250ma average current you will be somewhat limited in overall power. I suppose you could use a mot, voltage double it, put a big fat filter cap on it, and then use an interrupter to do short bursts using the energy stored in the cap
Registered Member #477
Joined: Tue Jun 20 2006, 11:51PM
Location: Seattle, WA
Posts: 546
The best use for an 866A these days is to make a nighlight. Well, ok, that would be fine if 866A's didn't generate X-rays I've got a few 866A's I've been searching for a reason to wire up. A friend used some in a homebrew linear amplifier for his ham radio station. I remember lifting the inspection plate and taking a peak at the 866A's glowing as he keyed the radio and thinking "Woa! Those are really cool!!" Mercury rectifiers are really neat to watch. The huge mercury arc rectifiers are even stranger, and are by far (IMO) the coolest tubes in existence.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Mercury rectifiers don't generate X-rays that I know of, since their forward voltage is only tens of volts. I used one for mood lighting for a while, and I still have all my hair and teeth:
Registered Member #477
Joined: Tue Jun 20 2006, 11:51PM
Location: Seattle, WA
Posts: 546
Steve Conner wrote ...
Mercury rectifiers don't generate X-rays that I know of, since their forward voltage is only tens of volts. I used one for mood lighting for a while, and I still have all my hair and teeth:
It is amusing that none of the 866A datasheets I can find say anything about this, however all six of my 866A tubes (RCA) have stickers on the bases warning of X-ray production (I'll take a photo tonight). Put the following into Google, too: 866A tube X-rays
I even found one page that talks about using an 866A specifically because it produces X-rays (for a homebrew X-ray machine. Yikes!
Hence I've been a bit reluctant to play with these.
Registered Member #546
Joined: Fri Feb 23 2007, 11:43PM
Location: Albuquerque, NM
Posts: 239
I found the same site refering to 866A's as a makeshift Xray tube by hooking it to the top load of a tesla coil....
My RCA 866A also has the x-ray sticker.
In normal usage however I don't think there's a great risk of exciting the plates enough to emit any hazardous amounts of radiation - nothing I've seen warns of that. just passing references to X-rays from putting the tube on a very high voltage source.
... so anyways I was digging around my dads old box of tubes and found a very interesting tetrode. It's 600V 4000W, water cooled and made out of silver, brass, and the heaviest glass I've ever seen in a VC. the whole tube weighs around 10 pounds. I asked if I could have it and he said no because it' the only one left in the world of it's kind. there were 5 made by his old company. He kept one, the rest went to the military.
Some... some day I'll have a very unique power tube to play with, but not today.
Registered Member #477
Joined: Tue Jun 20 2006, 11:51PM
Location: Seattle, WA
Posts: 546
Old tubes are neat stuff. I've got a couple of neat old radar modulator tubes, but getting data enough to actually use the tubes for something is the trick. A few of these were for the U.S. military, and the datasheets are unfindable (so far).
On the subject of mercury rectifiers: By far the coolest tubes out there (IMO) are the big, hot air balloon-shaped mercury arc rectifiers. Somebody just posted a video of one to YouTube. Not sure of its specs, but it would appear to be a big full-wave (three-phase?) unit. I'm sure the pictures don't do the size of this tube justice; these are enormous: http://www.youtube.com/watch?v=Rt-a8fxgtno
Unfortunately, thanks to the collectibility of them, they are nearly impossible to find, and nearly impossible to afford. The first person to employ one of these babies in a VTTC circuit will have forged a new axis on the coolness graph.
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866A for a VTTC?
But as the main driving tube, you'll have to do a bit more searching. VTTCs are a lot of fun to build though, so keep lookin for something suitable!
I've got a few 866A's I've been searching for a reason to wire up. A friend used some in a homebrew linear amplifier for his ham radio station. I remember lifting the inspection plate and taking a peak at the 866A's glowing as he keyed the radio and thinking "Woa! Those are really cool!!" Mercury rectifiers are really neat to watch. The huge mercury arc rectifiers are even stranger, and are by far (IMO) the coolest tubes in existence.
