Burn in small signal tubes?

karsten21 · 31st October 2011, 09:45 AM

Dear folks,

I often read that especial NOS tubes should be "burned in". Concerning high power types this might be necessary, but what´s about all these small signal tubes? Do it makes sens to "burn in" those tubes like 12ax7/EF86 and so on? And why should it be done?
Assuming it´s true how to do it? Let them run for a few hours in a center biased load line and input a white noise signal? Or it´s enought to heat the tube and let flow a anode current of say 1/2 max?

Thanks a lot for your annotations..

best regards
Karsten

Doz · 31st October 2011, 10:20 AM

Mr Bench wrote an interesting bit about EF86 here :Tube-Town Germany - Hot Stuff Cool Sounds
which I have bourne out in my experiments. Lower the heater for a bit, then bring it back up again. I repeat this several times. EF86 quietens down nicely and very quickly, without having to resort to 100s of hours of burn in time.

This is the only tube I've ever tried it on though, so I can't speak of 12AX7 etc.

SY · 31st October 2011, 10:25 AM

Yes, you want the getter to have a chance to clear out any residual gas.

Bigun · 31st October 2011, 03:24 PM

A bit off topic because these are not small signal tubes, but I had a chance to go through my box of ten 6S4S tubes in somebody's amplifier this weekend. Two of the tubes were not working - no sound. Then cracks and pops. After a couple of minutes they came to life and no issues afterwards. I guess this is burn-in ?

Tony · 31st October 2011, 06:34 PM

maybe the pins are tarnished.....

31st October 2011, 09:45 AM	#1
karsten21 diyAudio Member Join Date: Jan 2010 Location: Germany	Burn in small signal tubes? Dear folks, I often read that especial NOS tubes should be "burned in". Concerning high power types this might be necessary, but what´s about all these small signal tubes? Do it makes sens to "burn in" those tubes like 12ax7/EF86 and so on? And why should it be done? Assuming it´s true how to do it? Let them run for a few hours in a center biased load line and input a white noise signal? Or it´s enought to heat the tube and let flow a anode current of say 1/2 max? Thanks a lot for your annotations.. best regards Karsten

31st October 2011, 10:20 AM	#2
Doz diyAudio Member Join Date: Jul 2010 Location: Sat Down	Mr Bench wrote an interesting bit about EF86 here :Tube-Town Germany - Hot Stuff Cool Sounds which I have bourne out in my experiments. Lower the heater for a bit, then bring it back up again. I repeat this several times. EF86 quietens down nicely and very quickly, without having to resort to 100s of hours of burn in time. This is the only tube I've ever tried it on though, so I can't speak of 12AX7 etc. __________________ "To err is human.. to make a real balls-up requires a computer"

31st October 2011, 10:25 AM	#3
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Yes, you want the getter to have a chance to clear out any residual gas. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

31st October 2011, 03:24 PM	#4
Bigun diyAudio Member Join Date: Jan 2009 Location: K-W Ontario Blog Entries: 2	A bit off topic because these are not small signal tubes, but I had a chance to go through my box of ten 6S4S tubes in somebody's amplifier this weekend. Two of the tubes were not working - no sound. Then cracks and pops. After a couple of minutes they came to life and no issues afterwards. I guess this is burn-in ? __________________ "The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.

31st October 2011, 06:34 PM	#5
Tony diyAudio Member Join Date: May 2003 Location: Palatiw, Pasig City	maybe the pins are tarnished..... __________________ http://www.electronicslab.ph/forum/i...?topic=32688.0

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