New KT150 tubes?

I totally understand. I was told flat out "no" for my ART monos and ARTsa. I don't mind because I love them the way they sound and I'll take the chance if I choose to install KT-150's in my amps. At least we know of some ARC users actually using the KT-150 without problems. I suspect they (ARC) will never sanction the KT-150 and also suspect the Reference series and Galileo series are similar but we'll never know unless someone does a full breakdown.

ARC may not be the only vendor but there is only one manufacturer of these tubes. If I were you, buy the KT-150 and enjoy them. Life is way too short. You've already had problems because of a bad KT-120, I doubt you'll have any more or different issues with KT-150's. In fact, I believe the KT-150 will last longer and sound better.

I too waited anxiously for ARC to bless the KT150 s with the Ref 150 when I reached 2,000 hours on my KT120s in the summer. But they didn't, so I purchased another set of ARC KT120s.
I have owned 2 ARC amps and 3 preamps and have always purchased my tubes directly form ARC due to the comfort factor, but the reports were so good on the KT150, that I managed to meet with an insider at ARC who assured me that, unofficially, the KT150s were recommended for the Ref 150. Purchased a matched set from Upscale and can say they are better than the KT120s. Just sorry I didn't take that shot earlier cause I now have a full matched set of KT120s with only 500 hours on them.
Go with the KT150s. You won't regret it.

Bifwynne, I was a big ARC fans too. My first hifi preamp was ARC LS-1 in the 80's. I had used the 40th Anniversary and recently upgraded to Ref 10.

I brought a pair of Reference 250 last year and in the first week, one of them failed to power on after shut down. They were finally replaced. My recent experience with ARC have been fairly bad. Reliability is a real issue.

ARC had lost my support on power amp. My amp had been changed to Pass Labs and to me Pass Labs sounds better. It is kind sad to see ARC losing its long time customers.

I've been running four KT-150 in my VSi75 for about a month. At first I was enthusiastic. The sound has more power and more depth as somebody else already said. But, it sounds a little less "sophisticated". It sounds great, but has less finesse. Maybe that's the difference between something that is specifically designed around a specific tube. Anyway, if you like more power in the most basic meaning of the word, this is it. What a bargain upgrade.

PS: What I meant to say is that to me the KT150s sound much better. Out of curiosity (audiophilia nervosa) I plugged the KT120 back in a few times and even tried to mix both types of tubes but I always quickly returned to just using the KT150s.