I have a Blue Tune 903 that is giving me grief. Got it from a friend & fellow TBer, plugged it in,
left it plugged in for several days(!)- yes, stupid. After awhile the 12ax7 seemed fried, so I replaced the tube, which seemed to fix it. The pedal then sat unused for several months, went through a couple of moves(perhaps getting bumped fairly hard once or twice

)& just got unearthed the other day. W/the effect bypassed it's fine but engaging the tube it makes a loud hum/growl; no real 'signal'. replaced the tube- again- plugged it in & got 30 seconds of use before it did the same thing. I don't have the receipt, but the waranty card is in the box. i will call or email GB(Tube Works' parent co.)later but wanted to hit my TB bros first. Anyone ever have a similar experience?