...So the last two gigs I had intermittent volume issues with the 400+. Wed night at an Ivy League formal dance I didn't lose volume til the first encore. Something about my band (The Hep-Tet) makes it impossible to get to my amp during performance ( and I refer to that barrier as the Horn Section lol!). Just for the record I have a backup head, Eden WTX 260 in gig bag- but it was a marathon 90 minute set no break with those blasted horn guys as a defensive line. I am NO tech- but after looking at the 400+ chassis for about 10 minutes I figured even I could remove the 10 bolts and lift... I vacuumed about a lb of dust out with the house vac narrow needle tool, and I reseated about 3 power tubes that were starting to ride out of their socket. Trouble is in a house full of children and tiger wife it's impossible to repeat conditions and push it that hard for 90 minutes- but all the power tubes and preamp tubes have glow from Them. Next gig I make sure the Eden is plugged and ready probably with an A/B box. I think I'm gonna put in all new 12ax7s in the preamp, but I just can't budget $300.00 right now for power tubes. Anyone else ever have this volume drop on stage with a 400+?