Couple notes…I am a KR dealer and recently had a customer who had an issue with a tube that was DOA. I had them in-stock for more than a year prior to discovering the issue. KR replaced the tube, no questions asked and at no cost to me or the customer. I have heard about issues 10 or so years ago but KR is not an issue in terms of warranty. Just be certain to buy through an authorized dealer. There are people that claim to sell KR but do not and will sub in other things.
Regarding their KT150, last I checked they hadn’t made it for a while. I had these priced at $800 a pair but they were not a fast seller. I have note heard them.
I will say, the KT88s are stunningly good. At $250 a tube, they are not inexpensive. I have two matched quads in a pair of Art Aufio Opus 4 monos and they took what was already a great amp to a whole new level. I have also run Tung Sol KT120s and Genalex KT88/6550s in the amp and the KRs are dramatically better. Tighter bass. More detail. Better high frequency extension than either the Tung Sol or Genalex. They are pricier but I firmly believe I am getting better sound.
Regarding their KT150, last I checked they hadn’t made it for a while. I had these priced at $800 a pair but they were not a fast seller. I have note heard them.
I will say, the KT88s are stunningly good. At $250 a tube, they are not inexpensive. I have two matched quads in a pair of Art Aufio Opus 4 monos and they took what was already a great amp to a whole new level. I have also run Tung Sol KT120s and Genalex KT88/6550s in the amp and the KRs are dramatically better. Tighter bass. More detail. Better high frequency extension than either the Tung Sol or Genalex. They are pricier but I firmly believe I am getting better sound.