Maybe a short inside one of the tubes. Maybe request a refund from the tube seller.
Problem with tube rolling 6SN7s
Question from inexperienced tube roller here (hopefully not a stupid one). I'm running a Rogue Audio Stero 90 power amp with 12AX7(2) and 6SN7 input tubes. The stock 6SN7s are Chinese and don't sound bad at all but I have a set of NOS GE GTBs that I wanted to try. About 5 min after I installed these and powered everything up it tripped the protection circuit in my power conditioner. Any thoughts?