Old geezers and electronics buffs: get a load of this book I bought

[Commie Pinko Dirtbag]

at an used book stand in a Rio street. Vacuum Tubes by Karl Spangenberg, McGraw-Hill. It is from 1948, and it was printed in occupied Japan!

The book, in near mint condition


The innards of a beam-power tetrode tube


Gotta love those double integrals

[Dudley_DUright]

1. Nice partial differential equation (eq. 5.54) as well

I think we have this book laying around in my physics department. We also have a huge number of old replacement vacuum tubes.

[Commie Pinko Dirtbag]

3. Partial differential equations bring one to a higher level of awareness

Much like walking on burning coals.

[Another Bill C.]

2. I still have a tube tester in my basement.

I have an RCA tube caddy, too. You never know when those things will come back. How about that thoriated tungsten?

[Commie Pinko Dirtbag]

4. Thoriated tungsten's for the filaments, right? (nt)

[Dudley_DUright]

5. Yes, it lowers the "work function" so electrons are emitted easier

:-)

[hunter]

6. Hmmmmm, things that make you go...

Gas lantern mantels have thorium too. Extra credit, related or not?

I've built a few things with tubes, but not for a long time. I hide from people who use tubes in modern audio applications because I can't be expected to keep up with every religion.

Tubes are cool. It's amazing what tubes could be made to do.

[Another Bill C.]

8. Thoriated Tungsten

Thoriated tungsten is a coating used on the cathode. When heated by the filament, it starts emitting free electrons. It's sort of an "enhancement drug" for the tube.

[trof]

7. Heterodynes!

I think that's one of the books I had to study to get my Japanese radio-telephone operator's license.
I'm serious!

[DancingBear]

9. Tubes are the thing!

In present day audiophile circles, that is.

Nothing like the sound of an SET (single ended triode) tube design amp.

I currently (no pun intended) run two Brazillian designed SET amps (with Russian made "88" output driver tubes) coupled with very sensitive loudspeakers - ah, the sound...

BTW, the pre-amp is tubed, as well.

[Commie Pinko Dirtbag]

10. Brazilian amps, hm? I'm interested.

A friend of mine (at whose house I was yesterday) manifested interest in having tube amps. What's the maker of those?

By the way, he (who was my colleague at college) also went gaga with the book. He wanted to buy it. (Na na na na) He wanted to xerox it. (You must be kidding, right?) He settled for me lending it to him at some unspecified future.

[SoCalDem]

11. Off topic, but I am curious...

Are you a transplanted American, or a Brazilian with excellent command of English ?

[Commie Pinko Dirtbag]

12. Modesty prevents me from explicitly answering your question

Let's just say I am not, and have never been, a citizen or resident of the United States of America or any other English-speaking country. :hi:

[SoCalDem]

14. These days, that is a very good thing

:)

Brasil has always been a place I loved from afar.. I saw a teensy bit as a child when I visited Venezuela, but have never been back to SA..

Don't be modest:).. English syntax is difficult, and most ESL english speakers have a lot of trouble with it..

[Teddy_Salad]

16. Goode greaf!

Andd yor englesh is mutch bettar then mie Pawchewgeese.
At leest eye fink sew, aneeway.

;)

[DancingBear]

15. The amps are Audiopax

These are SET monoblocks, rated at 30 watts each.

I knew that Brazillian reference would get ya... :)

[DemoTex]

13. Plate voltage and grid current. Or was it plate current and grid voltage?

It's been a long time. I am now using a solid-state linear amplifier (1kw) with my ham rig. I miss the warm glow of vacuum tubes, though.



Svetlana, the Russian tube.

[Parrcrow]

17. You got your thumb in front of the camera

I hate it when I do that.

Cool find though.:toast: