Could this be a perfectly linear triode?

Merlinb · 24th July 2010, 10:49 AM

What do you think of this for a near-perfect linear triode?

I think I'll copy SY and let you guess what it is!

bigwill · 24th July 2010, 04:18 PM

Looks like a MOSFET with drain to gate feedback

smoking-amp · 04:21 PM

I notice some slightly doubled up lines for each curve. Some tube hysteresis factor or capacitance in the test setup maybe? Someone even mentioned recently an article by Norman Crowhurst about the absolute limitations of VT amplification accuracy due to vaccum tube hysteresis. But those doubled up lines look a bit too perfect for that.

And the clean separation of the curves at the bottom don't look like typical tube curves.
Some Mosfet contraption likely.

DualTriode · 24th July 2010, 05:30 PM

Hello,
Perfectly linear? No! The curves look straight, however they stack up (get closer together) from left to right. That means variable mu and not perfectly linear.
DT
All just for fun!

Merlinb · 24th July 2010, 07:25 PM

Ok, it's not perfectly linear, but it's pretty good right?

The doubled curves are mainly due to my curve tracer which uses half-wave rectification, so no doubt suffers some core hysteresis.

And I promise it is a real valve, not a MOSFET!

freddi · 24th July 2010, 07:37 PM

other than doubled lines looks pretty darn good - what's its safe plate dissipation? is it made from a pentode?

DF96 · 24th July 2010, 08:14 PM

Something high gain, but with cathode degeneration (i.e. unbypassed resistor)?

kenpeter · 08:21 PM

Mu somewhere in the mid 30's. Whats diff between this and 6dj8?

Actually transconductance is far less than 6dj8, so maybe 6N1P?
No, not even that good. What is this? Mini or nuvistor?

Slightly Schaded 12AX7?

Arnulf · 24th July 2010, 08:34 PM

Quote:

Originally Posted by Merlinb

Ok, it's not perfectly linear, but it's pretty good right?

Looks like ECC83 and yes, they look fairly good.

fdegrove · 25th July 2010, 12:05 AM

Hi,

Some nuvistor most likely.

Cheers,

24th July 2010, 04:18 PM	#3
smoking-amp diyAudio Member Join Date: Dec 2001 Location: Hickory, NC	I notice some slightly doubled up lines for each curve. Some tube hysteresis factor or capacitance in the test setup maybe? Someone even mentioned recently an article by Norman Crowhurst about the absolute limitations of VT amplification accuracy due to vaccum tube hysteresis. But those doubled up lines look a bit too perfect for that. And the clean separation of the curves at the bottom don't look like typical tube curves. Some Mosfet contraption likely. __________________ Ohms Law V = I R Last edited by smoking-amp; 24th July 2010 at 04:21 PM.

24th July 2010, 08:18 PM	#8
kenpeter diyAudio Member Join Date: Nov 2007 Location: Dallas	Mu somewhere in the mid 30's. Whats diff between this and 6dj8? Actually transconductance is far less than 6dj8, so maybe 6N1P? No, not even that good. What is this? Mini or nuvistor? Slightly Schaded 12AX7? Last edited by kenpeter; 24th July 2010 at 08:21 PM.

25th July 2010, 12:05 AM	#10
fdegrove diyAudio Senior Member Join Date: Aug 2002 Location: Belgium	Hi, Some nuvistor most likely. Cheers, __________________ Frank

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24th July 2010, 04:18 PM	#2
bigwill diyAudio Member Join Date: Dec 2004 Location: UK	Looks like a MOSFET with drain to gate feedback

24th July 2010, 05:30 PM	#4
DualTriode diyAudio Member Join Date: Aug 2009 Location: Sacramento	Hello, Perfectly linear? No! The curves look straight, however they stack up (get closer together) from left to right. That means variable mu and not perfectly linear. DT All just for fun!

24th July 2010, 07:25 PM	#5
Merlinb diyAudio Member Join Date: May 2006 Location: York	Ok, it's not perfectly linear, but it's pretty good right? The doubled curves are mainly due to my curve tracer which uses half-wave rectification, so no doubt suffers some core hysteresis. And I promise it is a real valve, not a MOSFET!

24th July 2010, 07:37 PM	#6
freddi diyAudio Member Join Date: Aug 2005	other than doubled lines looks pretty darn good - what's its safe plate dissipation? is it made from a pentode?

24th July 2010, 08:14 PM	#7
DF96 diyAudio Member Join Date: May 2007	Something high gain, but with cathode degeneration (i.e. unbypassed resistor)?

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