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Old 31st October 2011, 09:45 AM   #1
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Default 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 whatīs 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 itīs 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 itīs enought to heat the tube and let flow a anode current of say 1/2 max?

Thanks a lot for your annotations..

best regards
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Old 31st October 2011, 10:20 AM   #2
Doz is offline Doz  United Kingdom
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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.
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Old 31st October 2011, 10:25 AM   #3
SY is offline SY  United States
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Yes, you want the getter to have a chance to clear out any residual gas.
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Old 31st October 2011, 03:24 PM   #4
Bigun is offline Bigun  Canada
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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 ?
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Old 31st October 2011, 06:34 PM   #5
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maybe the pins are tarnished.....
planet10 needs your help: Let's help Ruth and Dave...http://www.diyaudio.com/forums/plane...ml#post5010547[B
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