Anyone used VS-110 with KT120 for extended period?

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.

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.

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

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

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.

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.