DT Tubes--is there only one choice? in DT50 / DT25 Posted February 12, 2015 My first pair of jj's were a great improvement in the noise floor of my dt25. Tone wise I don't know, a bit clearer and brighter maybe, but certainly no worse. They lasted about 3 months before one blew up. Second pair lasted about 3 months too (I play a few hours a week, always warming them up before leaving standby, properly biased, etc). After that I wasn't too enthusiastic over buying a third pair. So I stuck the remaining, unmatched tubes in instead, and even tho they are off by a good amount they have lasted much longer, must be over 9 months on each tube now. There's a slight hum but otherwise no other side effects that I've noticed from being unmatched. Perhaps its only SOME jj's which blow up? The sound quality difference is enormous compared to the stock tubes. Bogner designed a piece of lollipop if the best the amp can do is a choice between sounding noisy, or burning out the tubes every few months.