Large Rectifier Tube

[Benbmw]

Hello All,

I recently got in touch with a guy local to me who has a whole backyard and garage filled with mostly old electronics. All sorts of transformers, large capacitors, some large silicon, random rack mount test equipment, lots of vacuum tube amplifiers and all types and sizes of tubes. Basically a candy store for folks like us!

I wasn’t looking for anything specific on this visit but I did come home with a rather large ML-5576/200 rectifier tube, data sheet here: https://frank.pocnet.net/sheets/026/5/5576-200.pdf



Before this I was never really involved with vacuum tubes much aside from planning to build my own tube guitar amp and a VTTC at some point. However after laying eyes on this beast something awoke inside and I had to get it!

As you can see in the first photo the bottom socket is missing, however other than that the tube seems to be in working order. Although I may fire it up someday, the main interest was the novelty and I am currently using a nice piece of granadillo wood to make a display stand/base so that it can sit vertically on a shelf or desk in all of its glory. I will update with pictures once that is complete.

Now I am reinvigorated and wanting to make a GU-81M VTTC as my next project. Also, there were two other particularly large tubes that I might add to my collection (of 1) in the future. These were a Kuthe 1256 Hydrogen Thyratron: https://frank.pocnet.net/sheets/188/1/1257.pdf
Apparently the largest of its kind(?)

And an ML-LPT 44: https://frank.pocnet.net/sheets/026/l/LPT44.pdf
Which is an absolute chunk at 20lbs, mostly due to its massive copper anode.

Anyway, just wanted to share this and start to become more active on the forums. Hope y’all enjoy!

-Ben

[klugesmith]

Very cool, not in the literal sense.

Note 640 watt nominal filament power, 1000 volt worst case Vf,
and 1000 watt maximum plate dissipation.

But what's the alternative when you need 150 kV reverse voltage rating?

[Benbmw]

But what's the alternative when you need 150 kV reverse voltage rating?

Right! 150 1N4007s?

[MRMILSTAR]

I've seen diodes of this size used in older Cockroft-Walton voltage multipliers.

[Benbmw]

I've seen diodes of this size used in older Cockroft-Walton voltage multipliers.

That would be quite impressive!

Here is it with the base all finished:



And here are some “build pics”



Slight repair

And sanded flat again

[johnf]

You might want to consider it a room warmer (not heater) with that filament power
I've got a glass water cooled anode triode that has a kilowatt heater that I might do something similar to comes out of a 7.5kilowatt induction heater

[Benbmw]

I've got a glass water cooled anode triode that has a kilowatt heater that I might do something similar to comes out of a 7.5kilowatt induction heater

Wow nice! Would love to see pics of it. I have also considered trying to rig up some LED lighting, but there is a metal bulkhead type feed through where the wires enter that would prevent light shining up from the bottom, which would be the most elegant solution. I’ll have to brainstorm some other ideas.

-Ben

[Benbmw]

On a related note, does anyone know if there would be any noticeable glow other than the filament if this were conducting in the forward direction?

I know that mercury arc/vapor rectifiers have a nice purple glow, but this is a high-vacuum rectifier which doesn’t have any ions to emit a glow, correct?

Thanks,
Ben

[klugesmith]

Applause for the beautiful wooden stand.

You're right about the tube not glowing except from parts that are incandescent.
Unlike mercury vapor rectifiers, which can handle more current with much less Vf.


There are reports of some rectifier tubes, even vacuum-bulb incandescent lamps, having a glow from the glass envelope when voltage is so high that x-rays are produced.   I think that depends on their being traces of gas inside, as in Crookes tubes that were used as x-ray generators before Coolidge tubes were invented.

[Benbmw]

Applause for the beautiful wooden stand.

Thank you!

Those mercury vapor tubes are so pretty! I believe the guy I bought this from had another large rectifier that was of the mercury vapor type. Might be worth it for the glow 

Yes there is an x-ray warning on many of these data sheets for voltages >15kV. I was unaware that the glass itself would emit under x-ray excitation.

-Ben