Best/favorite CF NOS noval twin triode?

leadbelly · 16th April 2008, 04:51 PM

What I am looking for is a recommended NOS twin triode in the "standard" noval pinout (12AU7 etc.) for a cathode follower.

I know about the standard forum recommended 6N6P (not NOS) and 5687 (different pinout). I know 12AU7 is often called an "OK" CF tube but I was wondering if there was something better. Larger heater draw or different voltage is no problem.

SY · 16th April 2008, 04:56 PM

The figure of merit is gm, but you also have to consider desired drive current- a tube with 1mA of plate current won't drive a 1k load very well no matter how high the gm. For general purpose applications, it's tough to do significantly better than the ECC88 if you're limited to a dual package.

dsavitsk · 16th April 2008, 05:25 PM

That leaves the 8416 -- it is a 6dj8 with a 12.6V heater, which means it is pin compatible with the 12au7 with the exception that the heater has no center tap. So you have to use 12.6V to heat it.

SY · 16th April 2008, 05:34 PM

Shhhh! We don't talk about that tube!

dsavitsk · 16th April 2008, 05:37 PM

Oops, sorry. I forgot.

For what it's worth, I don't know that anyone is making 6N6p's anymore. they are NOS, just not US or EU made NOS.

kstagger · 16th April 2008, 05:40 PM

12BH7?

ok - not exactly a high transconductance tube.

dsavitsk · 16th April 2008, 05:47 PM

How about a 6DT8 or 12DT8. mu = 60, Gm=5500, and they are like $3 each.

Tubes4e4 · 17th April 2008, 08:29 AM

Hi Stuart,

Quote:

Originally posted by SY
For general purpose applications, it's tough to do significantly better than the ECC88 if you're limited to a dual package.

Indeed.

If more Pa and/or more Ia and/or more Ea-k is necessary than ECC88 could stand, the noval dual triode ECC99 might be of interest.

Regards,

Tom

oldeurope · 17th April 2008, 09:28 AM

Good moring,
I recommend the ECC83 12AX7.

Kind regards,
Darius

Geek · 17th April 2008, 10:01 AM

Hi,

Totem pole an ECC88 into a White CF and drive nails.

This modified White CF (mWCF) has an output Z of 100 ohms

(though repeatedly with various brands, it's about 120 ohms)

You heard it last year at Dave's I believe (back porch).

Cheers!

16th April 2008, 04:51 PM	#1
leadbelly diyAudio Member Join Date: Dec 2002 Location: Calgary, Alberta	Best/favorite CF NOS noval twin triode? What I am looking for is a recommended NOS twin triode in the "standard" noval pinout (12AU7 etc.) for a cathode follower. I know about the standard forum recommended 6N6P (not NOS) and 5687 (different pinout). I know 12AU7 is often called an "OK" CF tube but I was wondering if there was something better. Larger heater draw or different voltage is no problem. __________________ Aerodynamics are for people who can't build engines. Enzo Ferrari

16th April 2008, 04:56 PM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	The figure of merit is gm, but you also have to consider desired drive current- a tube with 1mA of plate current won't drive a 1k load very well no matter how high the gm. For general purpose applications, it's tough to do significantly better than the ECC88 if you're limited to a dual package. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

16th April 2008, 05:25 PM	#3
dsavitsk diyAudio Member Join Date: Jan 2005 Location: Chicago	That leaves the 8416 -- it is a 6dj8 with a 12.6V heater, which means it is pin compatible with the 12au7 with the exception that the heater has no center tap. So you have to use 12.6V to heat it. __________________ http://www.ecpaudio.com

16th April 2008, 05:34 PM	#4
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Shhhh! We don't talk about that tube! __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

16th April 2008, 05:37 PM	#5
dsavitsk diyAudio Member Join Date: Jan 2005 Location: Chicago	Oops, sorry. I forgot. For what it's worth, I don't know that anyone is making 6N6p's anymore. they are NOS, just not US or EU made NOS. __________________ http://www.ecpaudio.com

16th April 2008, 05:40 PM	#6
kstagger diyAudio Member Join Date: Dec 2003 Location: Grand Rapids	12BH7? ok - not exactly a high transconductance tube.

16th April 2008, 05:47 PM	#7
dsavitsk diyAudio Member Join Date: Jan 2005 Location: Chicago	How about a 6DT8 or 12DT8. mu = 60, Gm=5500, and they are like $3 each. __________________ http://www.ecpaudio.com

17th April 2008, 09:28 AM	#9
oldeurope diyAudio Member Join Date: Mar 2008	Good moring, I recommend the ECC83 12AX7. Kind regards, Darius

17th April 2008, 10:01 AM	#10
Geek diyAudio Member Join Date: Sep 2004	Hi, Totem pole an ECC88 into a White CF and drive nails. This modified White CF (mWCF) has an output Z of 100 ohms (though repeatedly with various brands, it's about 120 ohms) You heard it last year at Dave's I believe (back porch). Cheers!

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