Microphonic noise?

[DirtyNoise]

After I've been playing by SR at live gig level's....about an hour or so into things I begin to get a uncontrolable hum. I just replaced all the tubes..TAD, and gold tipped Tung Sol 12ax7s across the board.\
Any idea's what my be doing this? My TAD power tubes glow Hot Blue when they're really running. Thats ok right?

 

[mechanic]

Yeah, I use TAD 6L6s in my 2ch DR and they do glow blue. It's completely normal for those tubes.

 

[DirtyNoise]

Thats cool- I just don't see why it's doing it though. it could be the maxon od808 to some degree. Maybe I'll try backing off the Level some...even though I do not WANT TO