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
It would seem that the Death Star may be working on an 'Authorised' tech modification (cost of a handful of resistors and the odd cap unknown at this time) to some of the current production Ref/KT120 models, in order to optimise the utilization of the KT150, Ref 150se anyone!

This would of course enable relatively recent customers to retain any remaining factory/dealer warranty, whilst also affording the proud owner the facility of purchasing ARC factory tested sets of the new OPT's.

Curiously I raised the same point several weeks back, opine-ing, that as frustrated Ref owners were undoubtably going to go Off-piste anyway, that ARC may as well offer an upgrade service and make a few $$$ out of the situation, rather than expecting hordes of Ref owners to upgrade, lemming like, to GS, merely because they are the only officially sanctioned
models within the portfolio sporting the KT150.

Anyway, perhaps an avenue for you consider BiffWhine!
Tsushima1 ... I asked my ARC authorized tech to contact ARC's repair folks to find out if ARC is offering any kind of an upgrade kit for the current Ref amp line. He is unaware that such is the case, but said he would check.

I also asked him to try an get a definitive answer to my Q about using the KT-150s in my Ref 150. Namely, whether the KT-150s will damage or prematurely age my amp. I am looking for a "YES," a "NO" or "DON'T KNOW" answer.

I think he will get the "same old-same old" answer as the rest of us.
Here's an update. FWIW.

My ultimate goal is replace my ARC REF separates including Classic 120 monos with a very good integrated while maintaining (to some extent) the sonic attributes of my current set up. Discussing my options with an ARC dealer yesterday, he was saying that the GSI75 with KT150's is due out in early 2015. It will probably be introduced at CES in January for a release to market thereafter. He is checking with ARC to get a release date and wether it will sport a Phono stage and a DAC in the same box as originally announced by ARC a few months ago. Me, i don't think that they can put both in the same box for obvious reasons hence the delay.

OTOH, what about a REF75 with KT150. He told me that ARC will not ship a REF75 or REF150 with KT150 even if a customer ask for it and willing to pay the added cost. Although the specs are nearly identical for the REF150-GS150, he says that those are only the tip of the iceberg. The electrical design of the GS150 is different from the REF150 and is optimized for the KT150.

He is not sure if the amp is going to age prematurely with KT150. This is an ARC question to answer.
Thanks Smoffatt. Looking forward to learning about the circuitry changes in the GS-150. So far, the ARC web site gives no clue.