Mabonn, just a guess here, but I think it may be because the VT100 Mk II may not be user friendly when it comes to biasing the tubes. I've read somewhere that the bias pots are very close to some high voltage rails or contacts. If my surmise is correct, it's possible that Kevin may not sell you the KT-120s either for safety reasons. I know that he stocks both types of tubes. Btw, Kevin charges $90 for a pair of KT-120s, less than half the ARC price.
You should call him to see what the story is. Please report back. If Gary (Hifigeek) catches this post, perhaps he can weigh in about whether an electronics tech should install and bias the power tubes in a VT100 Mk II.
You should call him to see what the story is. Please report back. If Gary (Hifigeek) catches this post, perhaps he can weigh in about whether an electronics tech should install and bias the power tubes in a VT100 Mk II.