Tetrode output stage

nhuwar · 10th January 2007, 01:34 AM

I'm wondering is there a specific problem in using tetrode for audio power amp tube. I've been looking around and havn't seen any????????

Nick

ray_moth · 10th January 2007, 01:41 AM

You won't find any. The plain tetrode suffers from secondary emission that puts a 'kink' in the plate current / voltage curve at low plate voltages. This was cured by adding either a beam plate (to make a beam tetrode, e.g. 6V6, 6L6, 807, 6550, KT66, KT77, KT88, KT90) or a third grid (to make a pentode, e.g. EL84, EL34). All multigrid output tubes are either beam tetrodes or pentodes.

refference · 10th January 2007, 03:34 AM

Hi nhuwar , Hi ray moth ,

There is ( or there was ) a very interesting PURE
TETRODE made for AF Class AB1 or AB2 amplifier .
( among many uses ) .

It have two PURE TETRODES into the same envelope ,
made initially by Telefunken , I never see it , anytime ,
in any place , but I have two NOS of them on my shelf .

Don’t ask me about the sound quality , because I didn’t
build anything with us .

The two PURE TETRODES into the same envelope , allow
us to build a push-pull amplifier , with only ONE tube at the
output .

More information on the FRANK’s site – code # 6360
See page 5 of Telefunken 6360 datasheet .
Interesting to see and to know !!

Regards ,

Carlos

refference · 10th January 2007, 03:37 AM

OOOps , sorry , sorry !!

........ I didn't build anything with THEM .

Carlos

EC8010 · 10th January 2007, 10:00 AM

Although it doesn't explicitly say so, 6360 is a beam tetrode. You can tell from the anode curves and the symbols used on the pin-out hint at it.

SY · 10th January 2007, 11:09 AM

Quote:

Originally posted by EC8010
Although it doesn't explicitly say so, 6360 is a beam tetrode.

Impure! Impure!

nhuwar · 10th January 2007, 12:51 PM

So in other word's it would pretty much be a futile attempt to use tetrode.

Klimon · 10th January 2007, 02:30 PM

I asked the same question a while back: TETRODE amplifiers

Simon

nhuwar · 10th January 2007, 03:00 PM

I think it would make my life easier if I just use 2 triode. Plus there actually cheaper then the tetrodes. I've found a matching pair for $220 verses $250 each for the tetrodes.

refference · 10th January 2007, 05:07 PM

Quote:

Originally posted by EC8010
Although it doesn't explicitly say so, 6360 is a beam tetrode. You can tell from the anode curves and the symbols used on the pin-out hint at it.

Hi EC 8010 ,

Are you sure about that ???

I’m not sure , because over the entire bibliography available ,
the 6360 tube is mentioned and explicited how being a pure
tetrode , without beam plates or other tricks .

I , really , don’t want to broke the envelope of my NOS 6360
to confirm who has the reason !!! Or , if it is “impure” as
SY said !!!

Regards ,

Carlos

10th January 2007, 01:34 AM	#1
nhuwar diyAudio Member Join Date: Jan 2007 Location: Cypress Texas	Tetrode output stage I'm wondering is there a specific problem in using tetrode for audio power amp tube. I've been looking around and havn't seen any???????? Nick

10th January 2007, 10:00 AM	#5
EC8010 diyAudio Moderator Emeritus Join Date: Jan 2003 Location: Near London. UK	Although it doesn't explicitly say so, 6360 is a beam tetrode. You can tell from the anode curves and the symbols used on the pin-out hint at it. __________________ The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...

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10th January 2007, 01:41 AM	#2
ray_moth diyAudio Moderator Emeritus Join Date: Jan 2004 Location: Jakarta	You won't find any. The plain tetrode suffers from secondary emission that puts a 'kink' in the plate current / voltage curve at low plate voltages. This was cured by adding either a beam plate (to make a beam tetrode, e.g. 6V6, 6L6, 807, 6550, KT66, KT77, KT88, KT90) or a third grid (to make a pentode, e.g. EL84, EL34). All multigrid output tubes are either beam tetrodes or pentodes.

10th January 2007, 03:34 AM	#3
refference diyAudio Member Join Date: Jan 2006 Location: SAO PAULO - SP	Hi nhuwar , Hi ray moth , There is ( or there was ) a very interesting PURE TETRODE made for AF Class AB1 or AB2 amplifier . ( among many uses ) . It have two PURE TETRODES into the same envelope , made initially by Telefunken , I never see it , anytime , in any place , but I have two NOS of them on my shelf . Don’t ask me about the sound quality , because I didn’t build anything with us . The two PURE TETRODES into the same envelope , allow us to build a push-pull amplifier , with only ONE tube at the output . More information on the FRANK’s site – code # 6360 See page 5 of Telefunken 6360 datasheet . Interesting to see and to know !! Regards , Carlos

10th January 2007, 03:37 AM	#4
refference diyAudio Member Join Date: Jan 2006 Location: SAO PAULO - SP	OOOps , sorry , sorry !! ........ I didn't build anything with THEM . Carlos

10th January 2007, 12:51 PM	#7
nhuwar diyAudio Member Join Date: Jan 2007 Location: Cypress Texas	So in other word's it would pretty much be a futile attempt to use tetrode.

10th January 2007, 02:30 PM	#8
Klimon diyAudio Member Join Date: Apr 2005 Location: Leuven	I asked the same question a while back: TETRODE amplifiers Simon

10th January 2007, 03:00 PM	#9
nhuwar diyAudio Member Join Date: Jan 2007 Location: Cypress Texas	I think it would make my life easier if I just use 2 triode. Plus there actually cheaper then the tetrodes. I've found a matching pair for $220 verses $250 each for the tetrodes.