Bjesien, sorry but IMO, your comment is a bit hyped. As stated, I own a VS-115, which has KT-120 tubes. During the summer, I retubed the amp with the fresh KT-120s. Some time after, I blew a bias resister. The tube appeared to work (probably arced), but ARC recommended that I replace it, which I did -- at no cost.
I bought the tubes from Upscale Audio. Kevin Deal checked the suspect tube and it was ok. In fact he checked all the new KT-120s just to be safe. The bottom line is that the tubes were ok. ARC sent an authorized tech to my house to replace the bias resister -- again at no cost to me.
However, even if I had to replace the resister outside of warranty, the repair would have cost about $100. Most of the time charge would be travel. The tube costs $45.
I will go further. Tubes age; tubes blow. Same regarding bias resisters. If you like tube amps, it just goes with the territory -- no getting around it. So far, I consider myself quite lucky with my ARC gear. Very good build quality, great reliabiity and great sonics.
In short, I like the KT-120 tube. If one's amp can handle the extra power requirements, I recommend going for it.
