Oversized tube. What's it for?

[Audi0]

Anybody have any guesses? Yes it's at an auction. No affli

 

[maxhifi]

radio transmitter.

 

[Audi0]

They worth anything or just a decoration. To be honest they look like something scientist would have in a lab.

 

[maxhifi]

Those are definitely worth something. Still a very useful tube.

https://en.wikipedia.org/wiki/4-1000A

"A pair of tubes may be operated as an audio-frequency modulator for an AM transmitter; in this case a pair of tubes will provide up to 3,840 watts of audio power"

Man, now that would be impressive!

 

[gadget73]

you ain't kidding, yikes. Two of them single ended (stereo) would be plenty for me thanks.

 

[Dave451]

NOS $600 each. Whoa!

 

[Audi0]

There are more of those tubes there unmatched....

 

[rave0035]

They're cool. If you can get them cheap...

I just picked up some NOS 813's for $2, which put out a puny 330ish watts as AF power amps... and call for up to 2250vdc on the plates. Yowza!

Mike

 

[whoaru99]

They're cool. If you can get them cheap...

Yeah, if they can be had reasonable maybe there is some flipping opportunity. But, there is risk in that too.

For building an amp from those, well, that's an advanced project. Wrong move on those and all they'd find is your smoldering carcass from the 5kV plate voltage.

 

[bob smog]

I was on a plant tour for a job, and they had an RF heat sealer to form plastics. The tube was as big as my head.

 

[gadget73]

The tube that forms the heart of the electron beam setup at one of our other facilities is about a foot and a half tall and probably 6" around. Output from that runs into a big vacuum cavity where its accelerated by passing the beam around magnets a number of times to get it to the desired energy level. Freaky stuff. There was a problem with one of the beam forming magnets and the beam melted a hole right through the steel.

 

[AdamAnt316]

As others have mentioned, those are transmitting tubes, often used for large amateur radio RF amplifiers. I personally own an Eimac 3-500Z tube which has a fairly large bottle. Unfortunately, it suffered a nasty failure at some point, as pieces of the grid are floating around inside the bottle. Might make a nice base for a small table lamp, though..........
-Adam

 

[knockbill]

3800+ W,,, wonder what the speaker for that amp would look like!!! 811s are as big as I fooled with,,, Kept the Vp under 600V tho...

 

[KentTeffeteller]

Transmitter tube! For an AM or SW transmitter.

 

[whoaru99]

3800+ W,,, wonder what the speaker for that amp would look like!!! 811s are as big as I fooled with,,, Kept the Vp under 600V tho...

I'd be more than happy to try it out on some of my sound reinforcement speakers. Per JBL rating methodology, an amp of 1200 - 2400 wpc is appropriate. 3800 gives a little extra headroom.

 

[Jeffery]

I have a pair of 4-1000 as displays, as well as the 4-400, 4-250, 4-125, and 4-65 - and a bunch of other stuff.

 

[invaderzim]

3800+ W,,, wonder what the speaker for that amp would look like!!! 811s are as big as I fooled with,,, Kept the Vp under 600V tho...

http://i.imgur.com/ehr228G.jpg

 

[gadget73]

haha, that always comes up when people talk super power amps.

 

[century tek]

This has been around before. Not the same tube, but it looks like the output tubes are or could be a transmitter tube.

 

[Jeffery]

This has been around before. Not the same tube, but it looks like the output tubes are or could be a transmitter tube.

Those are 4-250s