12E1 Triode PP, Any Suggestion?

Kenneth Zhu · 30th December 2009, 02:23 PM

I heard that 12E1 had the best linearity among indirectly-heated valves, when being connected as triode. So I plan to build a PP with triode-connected 12E1s.

Is there any tested schematic to follow? Or any recommendations based upon real experiences?

Thanks in advance.

kevinkr · 30th December 2009, 03:58 PM

You could (and should) buy the book: "Valve Amplifiers, 3rd Edition" (Morgan Jones) I also highly recommend his book: "Building Valve Amplifiers" Both are highly informative, and entertaining.

Kenneth Zhu · 31st December 2009, 04:08 AM

Anybody can offer further help?

ja2dhc · 31st December 2009, 06:37 AM

Quote:

Originally Posted by Kenneth Zhu

Is there any tested schematic to follow? Or any recommendations based upon real experiences?

I find a schematic of 12E1 Tetorode PP, not triode connection at the
below URL.

http://www.audiopro.co.jp/kairozu/ap919bk.jpg

This amplifier is a product of Audio Senka in Japan. This schematic
is derived from QUAD-II.

I believe this amplifier is well tested for a selling product.

Quote:

Originally Posted by Kenneth Zhu

I heard that 12E1 had the best linearity among indirectly-heated valves,

I don't agree. The triode connection of GU-50 (=Chinese FU-50) has
better linearity than 12E1. Please refer to the attached photo.
GU-50(T) has higher plate impedance than 12E1. If two tubes of GU-50
are paralleled, the merged plate impedance is close to 12E1.

Jaap · 31st December 2009, 09:21 AM

The first schematic came from a british tubeseller with a large inventory of 12E1 tubes.
S11E12 is equivalent with 12E1, so you can also google on that tube.

davorin · 31st December 2009, 10:25 AM

Schematic of SE and SEPP classA amps.

Jaap · 31st December 2009, 10:33 AM

12e1 in se

Kenneth Zhu · 31st December 2009, 03:03 PM

Thank all above for the kind assistance.

In fact, FU50 is not as linear as 12E1 when being connected as triode. Moreover, generally speaking, tubes of Russian breed will produce coarser sound than those with British breed.

I will test the 12E1 triode PP schematic. But as first I will try to apply 400V to g2 of 12E1, though the theoretic tolerance is 300V at most, to check its stability in such working conditions.

SY · 31st December 2009, 03:04 PM

Quote:

Moreover, generally speaking, tubes of Russian breed will produce coarser sound than those with British breed.

That might be the single funniest thing I've read today.

Kenneth Zhu · 1st January 2010, 09:20 AM

Well. That's quite true. Usually the tubes from Western Europe will produce more smooth and sweeter sound than those from USA, Eastern Europe and USSR (Russia). This phenomenon is called as "Capitalist tubes better perform than Socialist tubes".

Go back to 12E1. According to test, in SE Triode mode, if being applied 360V plate voltage, this tube will produce 8W with 7% THD, mainly even order. And if being applied 420V plate voltage, this tube will produce 11W with 7% THD, mainly even order. This means that this tube has great potential for triode PP application, as even order distortions can be cancelled in PP applications.

30th December 2009, 02:23 PM	#1
Kenneth Zhu diyAudio Member Join Date: Sep 2003 Location: Deyang, Sichuan, P.R.China	12E1 Triode PP, Any Suggestion? I heard that 12E1 had the best linearity among indirectly-heated valves, when being connected as triode. So I plan to build a PP with triode-connected 12E1s. Is there any tested schematic to follow? Or any recommendations based upon real experiences? Thanks in advance.

30th December 2009, 03:58 PM	#2
kevinkr diyAudio Moderator Join Date: Sep 2004 Location: Boston, Massachusetts Blog Entries: 6	You could (and should) buy the book: "Valve Amplifiers, 3rd Edition" (Morgan Jones) I also highly recommend his book: "Building Valve Amplifiers" Both are highly informative, and entertaining. __________________ www.kta-hifi.net

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31st December 2009, 04:08 AM	#3
Kenneth Zhu diyAudio Member Join Date: Sep 2003 Location: Deyang, Sichuan, P.R.China	Anybody can offer further help?

31st December 2009, 03:03 PM	#8
Kenneth Zhu diyAudio Member Join Date: Sep 2003 Location: Deyang, Sichuan, P.R.China	Thank all above for the kind assistance. In fact, FU50 is not as linear as 12E1 when being connected as triode. Moreover, generally speaking, tubes of Russian breed will produce coarser sound than those with British breed. I will test the 12E1 triode PP schematic. But as first I will try to apply 400V to g2 of 12E1, though the theoretic tolerance is 300V at most, to check its stability in such working conditions.

1st January 2010, 09:20 AM	#10
Kenneth Zhu diyAudio Member Join Date: Sep 2003 Location: Deyang, Sichuan, P.R.China	Well. That's quite true. Usually the tubes from Western Europe will produce more smooth and sweeter sound than those from USA, Eastern Europe and USSR (Russia). This phenomenon is called as "Capitalist tubes better perform than Socialist tubes". Go back to 12E1. According to test, in SE Triode mode, if being applied 360V plate voltage, this tube will produce 8W with 7% THD, mainly even order. And if being applied 420V plate voltage, this tube will produce 11W with 7% THD, mainly even order. This means that this tube has great potential for triode PP application, as even order distortions can be cancelled in PP applications.

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