• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Homemade Vacuum Tube

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#2
Oh My, Interesting Stuff,
I Actually did .THIS PROJECT in the 60's as a science fair project in the 7th grade, Got to the state finals & honorable mention.

Our biggest problem was on the receiving end, The Photocell we used picked up to much light from the gymnasium lights and of course the dreaded 60cycle hum was very well amplified.

The following year we built a liquid laser! Mind you that lasers were in their infancy back then. Did I ever mention the effects of a 2 joule cap discharge on a human? :hot:

I probly shouldnt tell this story, (unless you all beg) But I will say that it is exactly why kids should NOT play with high voltage devices under the age of 16!

Trout
 
#5
Trout said:




Nawwwwww Valve Art for sure
😀
Click to expand...


Do Valve Art also suffer from apparently poor bake out, (leading to) incandescent grid segments and short lifetime issues also?

I NEVER saw such a quality problem trend with NOS tubes from the majors back in the good old days or surviving stock I use today.
 
#8
#15
Oxide Cathodes

Apparently, its possible to use a cathode recovered from a standard tube.....

BUT you must keep it above 120 deg C as its moisture in the air that degrades it when exposed to air.

It may be a little difficult to arrange this, but at least its possible to use the original heater to keep it warm....

You could try Carburised Tungsten if you can get hold of acetylene gas...

Bake the filament in atmosphere of acetylene under low-pressure to generate tungsten-carbide coating
 
#17
AlekZ said:
Lucky, my tube still alive🙂


http://www.trioda.com/php/forum/download.php?id=5398

I'd like to invite you to my page

http://www.trioda.com/alek/index_e.htm

so far there is poor english version, but I'm going to change it.🙂
Click to expand...

Beautifullll ! 😀
After many attempts I have found this fantastic thread.
My bigger problem is the workmanship of the glass
and my "neon maker" (can i say this for indicate the person
that build a cold neon signs ?) have say to me that i do
use a methane flame for melt the glass.

Experiments in progress ! 😀
 
#19
I recall reading a QST article from the early to mid 60's that described in some detail how a South American ham was building his own transmitting and receiving tubes, and had some pictures of his apparatus and description of his techniques.

I guess building your own tubes is the ultimate DIY.

Win W5JAG
 
#20
McGraw-Hill Electrical and Electronic Engineering Series:
Vacuum Tubes
Karl R. Spangenberg

Covers sundry topics such as selection of glass type, methods for achieving hard vacuum, metals, etc. etc. etc. Not a bad choice for those who want to know how they made tubes back when they still knew how to do it right.

McGraw-Hill Electrical and Electronic Engineering Series:
Fundamentals of Vacuum Tubes
Austin V. Eastman

A quick browse revealed a few tidbits that might be useful.

For that matter, most any of the old McGraw-Hill texts would be worthy reads for those who want to learn about tubes. They went into serious depth about the topic.

Grey
 
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