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
Sent another message to Kal. Waiting for a response. I asked him how the GS 150 differs from the Ref 150. The specs are identical, except the GS 150 uses KT150 tubes. I think there's a marketing wrinkle here.
I had an E-mail from someone who went to RMAF and noted an ARC ref 75, tubed with KT150's. I contacted the manufacturer, whom I won't name, but is a well respected US company. He kindly replied saying the KT150's are a straight swap with the same bias setting and no modification required. He also said he thought the sound was a real upgrade. I had already been told by a retailer for ARC, he thought this would be the case, but may not apply to larger amps using more tubes, such as the Reference 150.

When I have some time, I am going to be brave and find some KT150's and give it a go.
David, mere speculation, however I suspect that the ratio of output tubes to mains Transformer(s) might be the issue, rather than power output per se.
I have Ref 250 and my dealer told me I can just swap KT120s with KT150s without any modification . I am going to do this pretty soon.
Veerapaneni, has your (ARC?) dealer been given *Official* sanction from ARC Central for the utilisation of KT150's ?