Nope. I just have a run of the mill APC surge protector on everything.  I do unplug the 12B4 amp from it everytime I'm done using it though.  With it just running a two prong plug I don't like the idea of leaving it plugged in when not using it due to no safety ground. I measured the voltage coming from the outlet right after the amp blew the fuse and it was sitting at 120.4V.  Pretty low actually for around here.
I played the amp for a good hour this morning with no troubles that I could tell, so maybe it was just a weak fuse.