fire spark in 5AR4 rectifier tube for PrimaLuna Pr


All of a sudden, I see fire spark in one of the 5AR4 tube in my PrimaLuna Prologue 3 preamp so I turn it off immediately. I tried it again, and the same thing happen. What is going on?

Does it mean my tube is bad that I need to replace it? Or there is something wrong with my preamp? I did some research, it seems people said it may be the capacitance is too high, but I didn't change anything, could it be something goes wrong in the unit that results in capacitance being too high? Did I already damage my unit?

Thanks.
gte357s

Showing 2 responses by pehare

just replace the bad one...they don't need to be a matched pair. Although I'd probably replace the pair w/a nice pair of matching NOS & then keep the good single for a backup. enjoy!
GE, you can drive nails w/them, try Jim McShane Tubes or Andy at Vintage Tube Services.