Trivistor tubes?
May 13, 2002 at 1:38 PM Thread Starter Post #1 of 3

Rob N

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Has anyone heard of these?

Can't find anything about them on the internet.


Apparantly Musical Fidelity are going to use them in a new 20th anniversry range of products due Sept 02.They are going to produce 300 preamps,300 poweramps and 500 CD players.

In Hi Fi Choice mag there's an interview with Anthony Michaelson of MF saying that trivistors were like improved nuvistors but were only used in military applications and weren't produced until 1982!
 
May 13, 2002 at 10:09 PM Post #2 of 3

kwkarth

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Never heard of a "trivistor" but Nuvistors are typically triodes. Maybe it's a play on words. Looks like they're being manufactured by the Russians now, so supply problems should ease up.

http://www.tubes.ru/NuvistorTubes.html

Editorial comment:
After reading numerous articles regarding Nuvistors, it is evident that their development and the development of "compactrons" were last ditch efforts to forestall the obsolescence of the vacuum valve industry. If I had to go with a valve preamp, Nuvistors look like a great choice because of their inherent linearity, long life-span and low noise.
 
May 14, 2002 at 3:34 AM Post #3 of 3

PRR

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> Nuvistors... and the development of "compactrons" were last ditch efforts to forestall the obsolescence of the vacuum valve industry.

To that list, add the power tubes 7189, 7591 and 8417.

Nuvistors are the old acorn tubes with transistor-like packages. But the movement started before transistors loomed large. Compactrons and Novars, like the Miniature before them, were developed to reduce the cost of building radios and especially TV sets.

> Nuvistors are typically triodes.

BTW: there are several Nuvistor tetrodes and pentodes.

And in a long lifetime of playing with tubes, even counting some Nuvistors my father bought for experimentation, I have only seen five Nuvistors.

> Nuvistors look like a great choice because of their inherent linearity, long life-span and low noise.

None of these were compelling in the 1960s, and may not even be true.

The ONLY place they were widely used was in FM, TV, and Military radio, only on the front-end, often only the first tube. A few were used in instrumentation because their base leakage was reliably lower than commercial glass.

The Nuvistors in the standard RCA manual are no more linear than any other triode and worse than most that we would use for audio. Since the main use was for radio front-end, they are deliberately somewhat compressed at low current for good AVC.

There are a bunch of glass tubes that will meet or beat any commercial Nuvistor for low-Z noise. 417 blows it away, as will a true 6DJ8.

And long life..... many tubes "never" failed. TV tuners were hard duty because best performance demands high heat density. I have seen both Nuvistors and Minis live "forever", I have also had to replace a few of both types. The small size of the Nuvistor was a challenge to tube factories, one they did not always meet 100%.

Of course the deciding factor is that you can hardly get a Nuvistor today. And there are people with Classic Equipment who need spares more than you need a clever new amp. (And where do you buy a Nuvistor socket today?)

Naturally if the USSR kept the production going and is now willing to run them off for a boutique amp company, that's groovy. Even sexy in a way. But it won't be magic just because it has Nuvistors/Trivistors in it.

-PRR
 

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