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Nah

Mon Jan 03 2011, 11:39PM

Registered Member #3567 Joined: Mon Jan 03 2011, 10:49PM
Location: USA, 1960s
Posts: 260

Hi,

I was browsing the net, and saw this website, and since I like science, I decided to join. I'm not used to designing and building high voltage electronics, only low voltage electronics, and fixing vintage electronics, such as radios, tv, etc, that use vacuum tubes.

Could any one recomend any good starter info for a idiot like me?

Also, any projects that use components like the ones found is vintage radios, tvs, etc?

I have been lookign around, and I saw that quite a few of you build vacuum tube tesla oscilators. I'm used to being around tubes that output a couple of watts, like the 47, or the 6v6. I concider the 6L6 a high powered tube! Now these 811a s and these 833a s, now that is SOME power!

PS I don't know why some of you insist on using a tube wildly beyond it's ratings, your suposed to run a tube 3/4 of it's ratings, not 3/4 beyond it's ratings!

Myke

Tue Jan 04 2011, 01:04AM

Registered Member #540 Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969

I like to use this site as reference since it goes over the basics of most stuff including tubes. It's not the MOST in depth reference but it's a good start.

I really like the book called The art of Electronics as it explains things quite well, tries to avoid complicated math, and has depth.

For projects, you could design a small transmitter with a pentagrid converter tube, multiple oscillator topologies (Clapp, Hartley, Colpitts, Armstrong, VackÃ¡Å™, phase shift, etc.) that can be adapted to tube operation, or a small audio amplifier. There are many other things that you can build. Use your imagination.

EDIT: Wow I must be tierd... I forgot the link... Updated

ScotchTapeLord

Tue Jan 04 2011, 01:21AM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
Location:
Posts: 635

Nah wrote ...

PS I don't know why some of you insist on using a tube wildly beyond it's ratings, your suposed to run a tube 3/4 of it's ratings, not 3/4 beyond it's ratings!

Tubes aren't supposed to create artificial lightning, either.
We do it because we can... and we do it not only with tubes, but with IGBTs, capacitors, transformers, and much more.

If it's rated for 1000 hours of operation at 10 amps, we go for 100 hours at 20 amps (with a big, fan-cooled heatsink!).

If it's a big project, I prefer to run within spec for reliability. Otherwise, set the variac to 11 and keep a Class C fire extinguisher nearby.

Nah

Tue Jan 04 2011, 01:37AM

Registered Member #3567 Joined: Mon Jan 03 2011, 10:49PM
Location: USA, 1960s
Posts: 260

Well,

to tell you the truth,

I've always wanted to build a mercury rectifier night light.

I don't care what the ul says, it's safe!!!!!!!!

ScotchTapeLord

Tue Jan 04 2011, 01:52AM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
Location:
Posts: 635

No one cares what the UL says. People just like shiny stickers...

That sounds like a good project to document here in the Project section! I'm sure you can find people to answer questions about it if you have any. I'm more of a solid-state guy, though.

Nah

Tue Jan 04 2011, 01:57AM

Registered Member #3567 Joined: Mon Jan 03 2011, 10:49PM
Location: USA, 1960s
Posts: 260

One problem, a good 866a is around $60-70. And the power supply and ballest would be expensive. Perhaps a 83 would do.

Perhaps another day.....

Mattski

Tue Jan 04 2011, 07:08AM

Registered Member #1792 Joined: Fri Oct 31 2008, 08:12PM
Location: University of California
Posts: 527

Check out this guys website, some stuff here and more stuff here, he's got some cool stuff including homemade vacuum tubes and other homemade semiconductors.

Steve Conner

Tue Jan 04 2011, 12:26PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

I like building tube guitar amps and restoring old tube gear. I've been doing more of that than HV lately.

I have two mercury rectifiers that I bought with nightlight making in mind. They cost me about $20 each. The 866 is just expensive because it's well-known: mine are some obscure Mullard parts made in Holland. I believe the glass cuts out any harmful UV.

The power supply is easy, you just need a filament supply, and a plate supply that gives about 30V or more to strike the arc. Once struck it sags to about 10-15V, and your supply should be ballasted to deliver something like the tube's rated current. I used a 30V bench power supply to light mine. The only "gotcha" is that you must let the filament warm up before applying the plate power, and you also have to make sure that the filament power won't go off while the plate supply is on. (I had that happen to me. Pieces of red-hot cathode material shot around inside the tube and it generally looked pretty pissed.)

The smallest tube that makes a good tube Tesla coil is the EL509/PL509/6KG6, or a similar sweep tube from a largish TV.

Mark-H

Tue Jan 04 2011, 01:52PM

Registered Member #607 Joined: Tue Mar 27 2007, 10:39AM
Location:
Posts: 64

Before I got into mechanical TV and bike racing, I used to dabble in vintage tubes.

The Type 83 rectifier makes a nice glow.

The 807 can be used for a VTTC, but not really on its own. I used 4. It makes a very "handsome" rig.

Cheers.

Mark.

Nah

Tue Jan 04 2011, 08:08PM

Registered Member #3567 Joined: Mon Jan 03 2011, 10:49PM
Location: USA, 1960s
Posts: 260

Thanks!

Mr. Mc Connor, What type of mercury rectifiers would you recommed? I don't have any radios ot tvs that use mercury rectifiers, so I'm afraid I know little about them. I didn't know they could ionize at 30 volts! I would have thought 300 volt would have been needed. Well, time to do my homework!

I see that this whole site is full of VERY smart people, I'm just a repairman.

Hope I learn a lot from here,

Nah

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