New KT150 tubes?


Has anyone any experience with these pretty new tubes. There are already one or 2 amps I know of, that use them. The review of one of these amps in a UK magazine suggested they were a little warmer and more natural sounding than the nearly new KT120's

The article also suggested they were a straight swap for KT120 based amps, with no adjustment necessary. They are more than twice the cost of KT120's, but still not too costly compared with NOS tubes. I know changing from KT88's or 90's to 120's. did require some amp modification. I have an ARC reference 75 and might want to try the new tubes at some point, ARC don't seem to have a customer E-mail service, to ask the question
david12
Thank you David,

Let's hope we all get some official good news this year regarding KT-150's. I plan on ordering my first quad as soon as the stores are open. I'm looking at another week or so before they are installed and singing.

Happy new year everyone.

Bruce,

Keep the faith. I know of some reviewers and speaker makers who have been using KT-150's in their Ref 75's for quite some time with zero issues. Also, if you notice, the new ARC Galileo series of gear is not marketed as "reference" yet it is more expensive. Early reports are great but I'm not spending that much for them.
Joeinid .... the Ref 75 uses only 2 pairs of KT-150s. The Ref 150 2 quads. The Ref 250, I think 3 pairs per channel. My gut tells me that there is NO issue, but I am not a techie and I will not give advice or do something that is crosswise to ARC.

As far as the GS-150 is concerned ... yes it costs a small fortune. But other than a designer skin and a 2 tap (4 and 8 ohms) output tranny, I'm still waiting to learn how the innards differ from the Ref 150. On paper, the two amps spec identically.

Joe ... I'm annoyed because my tubes have 2000 hours logged on them and are ready (crying) to be replaced. One old tube already arced and took out bias resisters. I really want to use the KT-150s ... but won't because ARC has NOT sprinkled holy water on the new tubes.

I'm annoyed because ARC has had their hands on the KT-150s for some time now and should be able to report the results of life testing. I repeat what I said ... I smell a marketing trick here. Or, ARC doesn't have enough KT-150 tubes for current GS-150 production needs AND for current Ref amps.

Either way, it's annoying. If it's a cheap marketing trick, I'm pissed. If it's a supply issue, ARC is not the only tube vendor in town.
Your gut tells you there is no issue with 150s as does my previously noted survey. This must be digestion related.
Bifwynne, I agree that there seems to be "ulterior motives" , in ARC not blessing the use of KT150's in the reference series. It is a mistake too, no one is going to sell reference series amps to buy the new Galileo series, because they want to use KT150's. If it is policy not to pronounce on the new tubes, it is losing customer loyalty.

I have about 200 hours on my KT150 equipped Ref 75 and no problems at all, apart from not being able to put the lid back on. No biasing problems, excess heat from transformers, nothing. The only advice I have received from a dealer is, the more power tubes you need, the more risks to the amps there may be, so the Ref 75 would be the safest to re tube. I can not say if this is true or not. In any event, the KT150's are a big step up in the Ref 75, IMHO.
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.