12AT nos , flash at start ?

hi, is normal, when i start nagra pre, tube 12at7 make flash ?

like this

https://www.youtube.com/watch?v=PBjWmeuDurk

mati197904-03-2017 12:05am

mcintech Details Discussions Posts This discussion Message User 128 posts 04-03-2017 at 05:12pm Copy Comment URL Report Comment Edit Delete Perfectly normal in a Nagra preamp. (Full disclosure; am US service center for Nagra)