by sKiZo Thu Jan 09, 2014 7:58 pm
Probably best to never leave new tubes unattended. You want to be there if a one starts showing defects and red plating or exploding.
(Probably don't want to be there when one's exploding, now that I think on it a bit)
No specific burn in procedure required, other than listening. You do want to set the bias immediately, again after a few minutes with no signal, and one more time in another five. From there, just play some music at moderate levels. Recheck before putting it to bed, and again at the beginning of the next session. The tubes will more than likely wander around a bit for a couple hours even if they're supposed to be burned in when you get them. I like to get a couple hours on a new set before I crank em - they've usually settled down by then as all the little bits learn to play nice with each other.
I put meters on mine, so it's easy to check using those. I'll end up fine tuning the bias the first couple or three sessions after putting in a new tube set, but after that it's rock steady. I flip thru the meters on each tube every startup just to make sure it's ready, but haven't had to actually do any tweaking for some time now. I also still use a VOM every couple weeks anyway to double check to a greater level of accuracy than I can get with the meters - those read surprisingly well, but doesn't hurt to be on the safe side.
