Nuvistors – teardown / pictures

[mister_rf]

The 7586 Nuvistor type, manufactured by Hitachi.

RCA introduced the Nuvistor in 1959 as a miniature, rugged, metal-ceramic enclosed vacuum tubes, as a serious competition for the transistor.
The 7586 is a medium mu triode.

[mister_rf]

6С51Н-В (6S51N-V), equivalent to the 7586 Nuvistor.
Manufactured in the former Soviet Union,1975.

[SiliconWizard]

Cool vintage stuff.

Which makes me think, did you know about the Korg Nutube? It's still available and can be fun to tinker with for people willing to design small vacuum-tube-like preamps and the like, in a much more convenient form factor. Not cheap though.

https://www.korgnutube.com/en

[mister_rf]

The 7586 Nuvistor type, manufactured by Philips in USA.

[rsjsouza]

This is a seriously cool series of photographs. Thank you for sharing!

[james_s]

I wonder sometimes where vacuum tube development would have gone had transistors never been invented. I suspect we'd see some forms of vacuum integrated circuits at some point, constructed similarly to VFDs, and vacuum tubes the size of modern transistors or smaller.

[SiliconWizard]

I wonder sometimes where vacuum tube development would have gone had transistors never been invented. I suspect we'd see some forms of vacuum integrated circuits at some point, constructed similarly to VFDs, and vacuum tubes the size of modern transistors or smaller.

Did you take a look at the Korg part I mentioned? It's exactly that. Based on a VFD.

[CatalinaWOW]

Thanks for the pictures, particular the internal views.  I had never paid attention to construction and assumed they looked like smaller versions of their predecessors, just as the miniature base tubes strongly resembled their octal predecessors.  What a leap the nuvistirs we're.

[BrianHG]

I wonder sometimes where vacuum tube development would have gone had transistors never been invented. I suspect we'd see some forms of vacuum integrated circuits at some point, constructed similarly to VFDs, and vacuum tubes the size of modern transistors or smaller.

Here: https://www.extremetech.com/extreme/185027-the-vacuum-tube-strikes-back-nasas-tiny-460ghz-vacuum-transistor-that-could-one-day-replace-silicon-fets

[james_s]

I wonder sometimes where vacuum tube development would have gone had transistors never been invented. I suspect we'd see some forms of vacuum integrated circuits at some point, constructed similarly to VFDs, and vacuum tubes the size of modern transistors or smaller.

Did you take a look at the Korg part I mentioned? It's exactly that. Based on a VFD.

I remember seeing something about that when it came out. I was thinking something on a smaller scale though, as in complete flip flops and op amps in a package roughly the size of a DIP IC, and power tubes in a larger VFD-like package like that.

[SiliconWizard]

I wonder sometimes where vacuum tube development would have gone had transistors never been invented. I suspect we'd see some forms of vacuum integrated circuits at some point, constructed similarly to VFDs, and vacuum tubes the size of modern transistors or smaller.

Did you take a look at the Korg part I mentioned? It's exactly that. Based on a VFD.

I remember seeing something about that when it came out. I was thinking something on a smaller scale though, as in complete flip flops and op amps in a package roughly the size of a DIP IC, and power tubes in a larger VFD-like package like that.

Dunno if that could be miniaturized that much. Due to the structure having to withstand the vacuum.

I'd be curious to test those Korg things anyway. I've never designed any tube-based circuit, so that could be an occasion.

[TimFox]

An important detail about Nuvistor manufacture:
"Normal" tubes were assembled, sealed into a glass envelope, and then evacuated.
Nuvistors were actually assembled inside a vacuum chamber, including brazing the ceramic into the metal housing.

[T3sl4co1l]

I wonder sometimes where vacuum tube development would have gone had transistors never been invented. I suspect we'd see some forms of vacuum integrated circuits at some point, constructed similarly to VFDs, and vacuum tubes the size of modern transistors or smaller.

Well, physically speaking, semiconductors are inevitable.  On the most basic level, they work by promoting charge carriers across a potential barrier, and magic happens; in vacuum, this is the work potential, and electrons are the charge carriers.  In semiconductor, this is the band gap, and electrons -- or the absence thereof (holes) -- are the charge carriers.  Whereas thermionic or field emission is required in vacuum (and so far, no one's yet devised a reliable field emission cathode, I believe is the problem?), thermal "emission" at room temperature suffices in semiconductors.

Indeed, there are semiconductor analogs of vacuum tubes: of the pentode, the FET (minus the screen current and secondary emission "kink"); of the triode, the SIT (static induction transistor).  And the operating principle of the thyratron for example, isn't far from that of the thyristor -- in both cases a plasma forms, in the sense of abundant freed charge carriers crossing a potential barrier, the production of which is ~proportional to current flow (hence the low and ~stable voltage drop, and latching operation).  (Although I'm not sure that a thyratron analog of a GTO exists; perhaps a grid electrode could block charges very close to the cathode or anode (in the "dark" barrier around either), while being insulated in some way so it doesn't draw current itself, but that seems like several big "if"s.)

So, if it's any consolation... they still glow, just at far IR? 

Tim

[oz2cpu]

WOW thanks a lot for those fantastic nuvistor teardown closeups
your photo skils clearly shows :-)
I have not seen any pictures before about nuvistors that good.

i released a short video about some of my nuvistors

https://youtu.be/5NJbeDd6sJ4

[bidrohini]

I am cool with BJTs

[rdl]

Nice pictures. I remember some company made audio equipment using those. Maybe Musical Fidelity? I actually have a Nutube, but never did build the headphone amp it was meant for.