@markcasazza yep, clearly a New Sensor TungSol tube and supplier shortage again for sad reasons of war, yes, likely. Recently I checked my former sources and a few others. Some TS tube suppliers I know of are reporting the next round of TS output tube supplies might come back in stock in April/May. But, I would not count on it.
Also just for grins I’m checking with a former overseas source provider of the prior available KT120s that use to be with label by PSVANE as KT120s, saw those a few years ago but never tried them myself. Some other non-TS options would be nice.
As a backup I recently acquired up an older familiar SS amp to rotate in once in a while any time I want to give the KT120s and KT150s a rest. If that does not go well, will plan on obtaining an EL34 amp or something. Other options nice to have.