Nice triode

[sulcorebutia]

I prefer this "Power Triode" more



P.S. it is tube related, not OT

 

[Geek]

OK guys,
You got me . It´s Sonys old V-FET 2SK79.

Enjoy the data-sheet.

Anyway I got amazed when I saw it. Why don´t they continue to make tubelike sand?

Sooo.... why isn't this in the sand section?

Cheers!

 

[revintage]

Sooo.... why isn't this in the sand section?

´cause they don´t bother about triode lines there!

 

[Geek]

Good point...

Cheers!

 

[Wavebourn]

´cause they don´t bother about triode lines there!

Me neither. Both in Sand and Tube sections: when NFB applied it is not a big difference between triodes and pentodes; pentodes with NFB applied have even triodey curves than triodes with no NFB.

 

[Zen Mod]

Good point...

Cheers!

 

[revintage]

pentodes with NFB applied have even triodey curves than triodes with no NFB

That is, as I see it, correct if we talk voltage feedback.

If we add current feedback to a triode we get the opposite, pentodeish looking curves.

Still we want to find equidistant curves for linearity. This wether it is pentodes or triodes.

 

[Wavebourn]

That is, as I see it, correct if we talk voltage feedback.

Sure. Except, if somebody is a fan of so called "current driving" of speakers.

But in case of a NFB by voltage it does not matter is it local or global, anyway the end result is as if you use very linear triodes.

 

[pointy]

i must have been looking in the wrong place.

 

[revintage]

Except, if somebody is a fan of so called "current driving" of speakers.

I am talking local current feedback and single tube. But yes, Zout gets higher wherever you apply it.

 

[smoking-amp]

Here are some curves, for comparison, of a typical horizontal deflection tube in triode mode: 100 mA vertical axis, 200 V horiz. axis, Mu 4.2, gm 10,000 @ 80 mA

Don

 

[smoking-amp]

A now, a "triode" that eats 300B's for breakfast. Awesome linearity. 40W $1 each. Plentiful. (I have a box of 100) I'm not saying anymore.

 

[rdf]

I'm not saying anymore.

The Black Helicopters have been dispatched.

 

[Wavebourn]

A now, a "triode" that eats 300B's for breakfast. Awesome linearity. 40W $1 each. Plentiful. (I have a box of 100) I'm not saying anymore.

Let me guess... GU-50?

Röhren-Verstärker mit der LS 50 (GU 50)

 

[rdf]

Those are $2 a pop.

 

[Wavebourn]

Those are $2 a pop.

Not a big deal, anyway much cheaper than 300Bucks, and eats it on 300Breakfasts.

 

[smoking-amp]

UH-Ohhh I can hear chopper sounds outside. OH-No..... They took my box! Darn!
Well they didn't get the $2 dollar ones at least: (a common high gm video amp tube in triode mode, see attached)

I'll give you a hint on the mystery "tube", it uses Schading and has a 6DN3 damper in series with the "cathode".

 

[Geek]

Here are some curves, for comparison, of a typical horizontal deflection tube in triode mode: 100 mA vertical axis, 200 V horiz. axis, Mu 4.2, gm 10,000 @ 80 mA

Don

The curves LOOK like an EL36, but that much current would cook 'em

Cheers!

 

[smoking-amp]

"The curves LOOK like an EL36, but that much current would cook 'em "

The 1st curves are for a 6HJ5, a rugged 24 Watt tube. The 100 mA and 200 V figures are for the full axis (not per div., if that's what you were thinking). But a 6HJ5 will do a 1/2 amp readily. Futtermann used them for one of his OTLs. The triode curves are fairly similar for the other horiz. output tubes (18 Watt class) that I have looked at. Most of them have a Mu of around 3 to 4.7

 

[smoking-amp]

Well, lets take a look at some of the "black sheep" in the tube family now. Here is the triode in a 6KR8 or 6LQ8. Sort of an extreme version of the 12AT7. Notice the curves falling over to the right side. These may still work OK in P-P. But will have heavy 2nd Harmonic in SE.