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
FYI: ARC owners. I spoke with Chris Ossana from ARC on Monday about an issue involving the white Teflon caps in my Ref 5 SE and Ref 150.

During the course of the call, I asked Chris about the KT-150s ... again. Chris continues to tow the company line. Chris said that ARC engineering has NOT approved the KT-150s for use in the current Ref amps; only the "new" GS-150 amp.

No one could say they are a bigger ARC fan than me, but I am getting big time irritated by the approval lag. ARC has been life testing the KT-150s for well over a year. I admit that I am not a techie, but from what I can glean from the web, aside from a little more current draw, the "120s" and the "150s" spec almost identically.

Further, ARC's published GS-150 specs look almost identical to the published Ref 150 specs. I smell a marketing rat here.

Even still, I will not chance risking my amp until ARC sprinkles holy water on the KT-150s. But I am getting annoyed big time.

My KT-120s are ready for replacement. I already blew 2 bias resisters because an old tube arced. I would like to buy 2 quads of KT-150s from Upscale Audio but am waiting on ARC. As I said above, I smell a marketing trick to sell the "new and improved" GS-150 that specs identically to the Ref 150, but for the KT-150s.

Sorry for the cynicism.

Happy New Year.

Bruce
Wow! your art amps are impressive,that's a good way to go ,to try it on the smaller amp first.I usually see Bill and Lew at ces ,2 years ago they were raving about how much they were liking the kt120's,last year they were not officially at the show as vendors ,but I ran into Bill ,Lew ,and Jeff their engineer in the hallways at the show .I asked about the kt150 and Bill said he had just acquired some but hadn't had a chance to test them yet .Jeff was concerned because of the higher filament voltage and that my amps transformers were not optimized for that tube,Bill didn't seem to be worried that the amp couldn't handle it ,more that,some of their customers still like to use 6550's and thats what the amps were designed around.Anyways I have always been a huge fan of there products and enjoy my amps and my ct5 pre amp,maybe someday art's.thanksagain
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.