Burning-in Vacuum Tubes

[PublicMelody]

I'm retubing my Demeter VTCL2 Comp/Lim, using NOS and new tubes.

Is there a burn-in period for tubes? I've heard tell of such, but don't know a thing about it.

Thanks,

- Jim[/list]

[Scodiddly]

I wouldn't worry about it. If the tube is good, it's good. Don't sit around NOT recording because you think you need to "burn in" your tubes first.

[PublicMelody]

Found this:

http://www.sweetwater.com/expert-center ... 12/08/2000

[emrr]

A new tube can have stray electrons in the vacuum, and they get attracted to the plate with use, which makes the vacuum cleaner. The stray junk can cause noise, and I've seen many tubes get quieter over the first week of heavy use. This is also true of used tubes that have been sitting around for years.

The Radio Designers Handbook gives a test jig description and procedure for burning in new tubes for stability before testing and noise selection.

[ceilingcat84]

How long do new tubes generally take to "burn in" as opposed to old ones that have been sitting around for a while? Does it depend on the type (triode, pentode, etc)?

[emrr]

if I recall correctly, the industrial method is six days constant, with all elements tied together and only heater voltage applied. Of course can't find it in the 1200 page book right now. There is no method described for used tubes, I've just experienced the phenomena. Doesn't depend on type that I know, but I'm sure someone could find some differences. I've heard NOS tubes have intermittent noises over the first heavy week of use and then calm down permanently. Without patience, you might throw these out and consider them faulty.

[Recycled_Brains]

i just bought a couple of NOS tubes (mullard and amperex) to try out in my Charter Oak mic, and Mike (the mic designer) recommended i burn them in for 48 hours or so before use (as did the fella that i bought the tubes from).

he basically explained that at first, NOS tubes can be a little noisy, and that after a couple days of burn-in time, that noise should be alleviated, and that you'll get a more accurate indication of the quality the tube imparts on the sound of whatever device you're using it in. even with the brand new, stock, tubes he uses, he said that he burns them in for as long as possible before shipment.

i'm no expert, so i'll take his word for it. he's a smart fella.

-ryan

[pandatone]

i dont' know anything. but im a curious kinda person.
when "burning". do you just turn your preamp on. (or whatever tube device)
and leave it on for XX period of time? or you run a singal through it? or is their a device for actually burning in tubes?
sorry for the basic questions. but, i don't know and can't find the answer.

thanks!

panda

[Recycled_Brains]

when "burning". do you just turn your preamp on. (or whatever tube device)
and leave it on for XX period of time?
panda

yup.

-ryan

[pandatone]

yup.

thanks! good to know.

panda