Anyone used VS-110 with KT120 for extended period?

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.

Just be careful if you ever blow a resistor because ARC will also charge you for a new set of tubes. This has been my experience two times. A fifty cent part can easily turn into a few hundred.

I won't buy ARC again.

Thanks for the response guys

Any suggestions on how to bias the KT120 for the VS110? Same 65mV as the 6550Cs?

I am now waiting a verification from ARC for the tubes

Flip Brent Jesse an e-mail or access his web site and you will get an informed opinion.

I own a VS-110 and replaced the 6550's with KT-120's 6 month's ago. I have had no problems with about 400 hours on the KT-120's. My experience with sonic improvements are the same as Bifwynne. I would heartily agree that you move to the KT-120's.

I own an ARC VS-115. I replaced the 6550C tubes with KT-120 tubes. The sonics were improved across the board, especially the bass which is much tighter with much better slam. IMHO, it's a no brainer.

My only caveat is that you should call ARC and ask Calvin if the VS-110 can handle the KT-120. I suspect that it can, but you should check with Cal. You can also ask Cal for his opinion on swapping out the 6550C tubes for the KT-120s.