Another new Tube, this time from Korg?

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Leo_Gnardo
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Re: Another new Tube, this time from Korg?

Post by Leo_Gnardo »

"Built to the highest standard . . . offer up to 30,000 hours of service life . . . The high reliability meansthat it can be attached directly to the circuit board with confidence knowing that it will not need to be replaced regularly like a 12AX7."

tube rollers bound to be disappointed.

tubes soldered to board, I smell trouble.

If nothing else, one more step to disposable amps.
down technical blind alleys . . .
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gui_tarzan
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Re: Another new Tube, this time from Korg?

Post by gui_tarzan »

And then from NASA, there is this:

Link
The vacuum tube strikes back: NASA’s tiny 460GHz vacuum transistor that could one day replace silicon FETs

NASA’s Ames Research Center has been working on-and-off for many years on the vacuum-channel transistor, which is essentially a vacuum tube that can be fabricated using conventional CMOS techniques. Instead of a gate sitting between the source and drain, there is… nothing. A vacuum. By a method known as field emission, electrons are drawn across the vacuum from the source to the drain when a current is applied to the gate (see diagram). By using field emission rather than the thermionic (hot) electron emission, these vacuum-channel transistors don’t require a heat source. Importantly, they also don’t require a vacuum — instead they use helium (it’s sparse enough that the electrons have almost no chance of bumping into helium atoms while they traverse the few-nanometer gap between source and drain). The electrons also traverse the air gap a lot faster than if they had to pass through the gate electrode.
--Jim

"He's like a new set of strings, he just needs to be stretched a bit."
shoggoth
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Re: Another new Tube, this time from Korg?

Post by shoggoth »

Sounds like they've repurposed some VFD (vacuum fluorescent display) manufacturing capabilities for audio.

I recall reading somewhere about someone using VFD's for audio amplification ? Seemed gimmicky, but this is purpose-built, so may be awesome.

Not having to deal with high voltages would be nice. Power amp would need to be transistors presumably. If these go on sale somewhere I can get them, I'll pick up a bunch for sure.
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Structo
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Re: Another new Tube, this time from Korg?

Post by Structo »

Yeah, but where do they fit the crystal lettuce?

I'd like to see the specs on it.

Just cause it has a pretty window doesn't mean diddly.


[img:327:218]http://www.noritake.co.jp/company/press ... _04a-s.jpg[/img]
Tom

Don't let that smoke out!
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Phil_S
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Re: Another new Tube, this time from Korg?

Post by Phil_S »

It's helium filled? Your guitar will sound like Donald Duck!
Wait until you find out what it sells for. Unobtainium pricing?
tubeswell
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Re: Another new Tube, this time from Korg?

Post by tubeswell »

Gaaaarrggghhh!
He who dies with the most tubes... wins
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RWood
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Re: Another new Tube, this time from Korg?

Post by RWood »

The crappy old technology of vacuum tubes is precisely what makes them sound good to my ears.

They can use new technology to mine asteroids.
If it don't get hot and glow, I don't want it !
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JMFahey
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Re: Another new Tube, this time from Korg?

Post by JMFahey »

After reading it in (initial) disbelief, this struck me as one of those "how didn't I think it before?"

Yes, it's based on Fluorescent display technology, available since ... 1959 :shock:

http://en.wikipedia.org/wiki/Vacuum_fluorescent_display

[img:438:295]https://c2.staticflickr.com/4/3131/3087 ... c43881.jpg[/img]

and yes, those are real triodes, with real vacuum, cathode (direct heated I presume) , grid and anode/plate .

Only difference is that plates are not covered in some fluorescent material and instead of being tied straight to some high voltage supply (think 45 to 90V , not 250/300V) they probably do so through some honest plate resistor, so as to get signal out of them.

Brilliant (no pun intended) idea.

Japan and direct heated triodes in the same phrase?

Why doesn't that surprise me? ;)

What does surprise me is that this was not done 50 years ago.

And above suggested pin count looks very logic, for 2 direct heated triodes.

The window may look gimmicky but let the guys show off a little ;)

And ... is it really?

Fluo displays are glass enclosed, not only to be seen (duh) but because they are real vacuum tubes.

I bet datasheets will be available soon.

EDIT:
Design

The device consists of a hot cathode (filaments), anodes (phosphor) and grids encased in a glass envelope under a high vacuum condition. The cathode is made up of fine tungsten wires, coated by alkaline earth metal oxides, which emit electrons when heated by an electric current. These electrons are controlled and diffused by the grids, which are made up of thin metal. If electrons impinge on the phosphor-coated plates, they fluoresce, emitting light. Unlike the orange-glowing cathodes of traditional vacuum tubes, VFD cathodes are efficient emitters at much lower temperatures, and are therefore essentially invisible.[4]

The principle of operation is identical to that of a vacuum tube triode. Electrons can only reach (and "illuminate") a given plate element if both the grid and the plate are at a positive potential with respect to the cathode.
I'm impressed.
shoggoth
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Re: Another new Tube, this time from Korg?

Post by shoggoth »

Hopefully there are separate heaters for each triode, so each can be biased separately.

Directly heated triodes are a minor pain to bias (I use diodes for that), and the filament supply needs filtering at each filament to keep crosstalk between the tubes to a minimum. BUT, it can be done. Just extra components. Not a huge deal.
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JMFahey
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Re: Another new Tube, this time from Korg?

Post by JMFahey »

Given the pin count, probably you are right, each one its own filament/cathode.

As far as biasing, (I'm guessing here because I've seen no datasheets yet), they may be built so they all bias at, say, 1 mA with , say, -1V fixed grid bias (easy to get).
Then all cathodes can be grounded ... or more properly referred to ground, maybe 1 filemant end grounded and the other being fed DC.

For those who find fixed bias in a preamp weird, remember tubes were originally powered with batteries: A , B and C .
A being filaments (2 or 6V)
B being high voltage (still called +B ;) )
C being bias.

The cathode resistor self bias is a "modern" invention designed to save 1 battery.

By the way, C batteries were used up to the 40's, they gave no current (not needed anyway) but provided very stable 1.5V for years.
Early techniques

Early experimenters and manufacturers used a battery to provide this bias. This battery, called the "C" or bias battery provided voltage but almost never was called upon to deliver current. Thus, such batteries lasted nearly as long in service as they would have on a shelf. In 1985, The Department of Engineering and Technology at Cuesta College in San Luis Obispo, California was presented with a "C" battery date stamped 1927. Department Chairman W.E. English and Instructor W.T. Hanley conducted experiments which demonstrated that the battery still performed satisfactorily in its originally intended role more than 50 years after its manufacture.
This one provides 6 different voltages.
The -1.5 and -3 V are good for most any preamp tube, even "modern" (think 12_7 are 60 years old or more) and the -9V might be enough even for power tubes (think 2W radio and phonograph outputs, not EL84 or 6L6) .
teemuk
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Re: Another new Tube, this time from Korg?

Post by teemuk »

Not mine....

https://www.youtube.com/watch?v=LEAhRayjNS0

...but basically, why wait for "NuTubes" when those VFD's are already out there in legions.
matt h
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Re: Another new Tube, this time from Korg?

Post by matt h »

(deleted)
Last edited by matt h on Fri Mar 27, 2015 3:58 pm, edited 1 time in total.
ampgeek
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Re: Another new Tube, this time from Korg?

Post by ampgeek »

I love that dudes workbench/work area!

Suddenly...I don't feel so bad whenever I stop to survey my "kingdom"!!

Seriously though, pretty cool to see something like that actually function.

Cheers,
Dave O.
teemuk
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Re: Another new Tube, this time from Korg?

Post by teemuk »

I think this is the site related to that youtube clip I posted:

https://web.archive.org/web/20111130050 ... rr-vfd.htm

On a serious note, I wonder if ordinary VFD's can be hacked to replace these "NuTubes". Because in ten years people who repair that Korg stuff probably will be pondering the same thing. Given planned obsoletion of devices like OTA's and BBD's (and everything else of "niche" special purpose) what do you think are the chances that "NuTubes" are still produced after the initial hype has worn off in few years?
SoulFetish
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Re: Another new Tube, this time from Korg?

Post by SoulFetish »

This seems to be the latest development in what appears to be a renaissance of vacuum "tube" technology. Personally, I'm exited that engineers are currently exploring new innovations into this technology and investing in this market.
Maybe they were inspired by the news of scientific breakthroughs in vacuum-transistor hybridisation covered in this article:

http://news.sciencemag.org/physics/2012 ... acuum-tube

In any case, I'm looking forward to getting into the datasheets and experimenting with these. Maybe these pick up where Nuvistors left off many years ago.
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