Quiz: which tube is this?

[SemperFi]

So....Gurus and others.
1. Which tube do these curves belong to?
2. Do the curves indicate a linear tube?
3. Would you use it for a PP amp or a SE amp?

 

[hidnplayr]

I think it is very hard to tell if you dont give any numbers 😉 (volts/div, milli-amps/div)

 

[SemperFi]

I don't want to make it too easy. But ok. 20 mA/div vertical and 20 V/div horisontal. I aint saying nuttin bout grid voltages yet.

 

[Wavebourn]

Volt/ampere diode characteristics on different filament currents?

 

[TheGimp]

Regulator triode, low voltage and high current capability.

 

[hidnplayr]

It reminds me of EL36 in triode, but the voltages dont work out 🙂

 

[kavermei]

Is that hysteresis I see?

 

[ja2dhc]

2A3

 

[SemperFi]

6AS7! Not bad Gimp.
Mohahahaha! U guys keep up the 'it's so nonlinear' and let me have all the fun. Keeps the price down. 😀

 

[smoking-amp]

Looks like you only have 20 Volts of grid change on that earlier plot. Here's the rest of the curves:

Plotting most any load line on them shows a 2 to 1 change in gain from one end to the other. Umm... 100 % distortion? Probably work OK in P-P though, where all that 2nd Harmonic would cancel.

edit: added curve trace of a low distortion triode for comparison (not a 300B, this only costs $3)

 

[smoking-amp]

OH, sorry. I think a 2 to 1 gain change is more like 20-25% distortion in class A.

That's at max amplitude of course. The dominant 2nd H distortion varies quadratically with amplitude below that. Would have to hit the books and a load line on the curves to calculate it the precise way from tangents/chords and all that.

2nd harmonic would cancel out in P-P anyway.