Tubes: How long to break in?

[nikongod]

Quote:

Originally Posted by sdgserv /img/forum/go_quote.gif When they die will they see a bright light?

lolerskates.

i had a tube failure in one of my amps.

the gain tube got all hisssssy. i was like crap, lets finish the side of this record.

then there was a crack more beautyfully like the breaking of a thin glass rod that i have ever heard recorded.

i looked up and one of the plates on the output tube was glowing kind of between red and white. the tube filled with a purple blue glowing "plasma" (it may have just been free electrons) and i quickly unplugged my headphones and turned the amp off.

when the output tube cooled i immediately threw it, its mate and the gain tube in the trash. the real irony of this is that the tube that caused the failure tested good a week before.

the amp gave obvious warnings for about an hour before it went poof, but since then i dont leave anything but my millet on overnight. i do leave my tubes running if i go to the bathroom or to the kitchen for a beer...

 

[Skylab]

My feeling is that once the tubes are quiet, they're ready to go. Sometimes this is very fast, sometimes it can take 20-30 hours (like with 6SJ7's, for example).

 

[zipdisk]

My strategy (or ritual) is to turn the equipment fully on and let the new tubes outgass for about 4 hrs without a signal, then listen to a cd or two (my first inkling of what to expect), and then leave it fully on to outgass overnight. After that it can take anywhere from 5 to maybe 50 hours for the tubes' sound to mature. (I use 6922 and 12ax7 tubes.)