Sovtek KT88 Vacuum Tube

got a quad set 2 right out of the box were bad blew up pop fuse on my jolida 502, parts express great about replacing they sent me 2 new ones no cost got them 2 days, this time worked and sounded good, lots of gain, just like i have read, all good things about sovtek kt88's, but about 50 hrs later another poped like a light bulb, so went back to the EH'S built like a tank, but i didnt get them from parts express, i was concirned about their packaging/ shipping.