Yep, tubes are often a coin toss (especially so in a new amp IME). The only issue I ever had with my my new SVT VR was a couple of preamp tubes going down. As I posted earlier, I replaced all the preamp tubes in my 100T with JJs and put Winged Cs in for the power tubes - sounds great to me and has been totally reliable (to be fair, it sounded great and had no issues before the replacement too
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